A bad teacher is one who can't impart knowledge to his or her students. A good teacher is one that can explain a problem and a solution to the problem. In this video, I would rate you as a GREAT teacher.
Finally I found a video showing what these stupid widebands should look like and read on a scan tool! I swear this is the only video on RUclips that actually shows it! Thank you so much! I'm in the middle of diagnosing a 5 wire sensor on a buddy's car and now I can be confident that it's faulty and needs replacing! Thanks a lot again sir! Great video!
Just found this gem after watching 100s of newer videos. I understood everything you were explaining and enjoy your in depth analysis. I have no clue if I will ever use it in my lifetime....
I learned so much from your video. Most importantly...The front sensor is NOT an O2 sensor but a air/fuel ratio sensor!!! I was about to change this sensor on my buddy's 03 Tundra as my scan tool gave me flat line readings and not a sine wave. Turns out, this is normal. You saved my friend $180 because that is what the Denso part cost. Took me half dozen YT vids to find the one that gave me the right answer and that was this video. Thank you!
Eric, my understating is that when you're reading an AFR signal in OBD II mode, you get 1/5 the value of the AFR reading in Enhanced MODE. Therefore, if the Enhance mode reading of the AFR sensor is 3.3 Volts, in OBD II mode you will read the AFR Voltage as 0.666 V which equals 3.3v/5v = 0.66 Volts, in addition during acceleration in OBD II mode, the AFR signal in OBD II value will display about 0.5 V, which equals a AFR Voltage (enhanced mode) of 2.5 V (equals rich mixture); therefore 2.5 V/5V = 0.5 Volts. Also, as you mentioned, further testing and confirming the AFR sensor is operating correctly, you could remove the harness side connector of the AFR sensor, put the probes of a VOM or a Scope between the two signal wires of the AFR sensor (while AFR sensor is still in exhaust pipe) , jump the two heater wires from the disconnected Harness connector to the heater wires on the AFR sensor heater wires ( helps keep the AFR sensor at optimum Temp while conducting this test) , you will get an Analog signal ranging from about 0.8 V to about 0.2 V just like a Narrow Band O2 sensor. This confirms the correct operation of the AFR sensor if you do not have the ability to Read Enhanced mode data. Thanks for the great video!!! What Amazes me is how is it an ASE Certified Toyota Dealership Tech could not identify and confirm a faulty operation of this AFR sensor, Amazing !!!!!!!!!!
2006 Toyota Camry. Drive cycle wouldn't complete 3 months. Changed the Air Fuel Regulator in the CAT. bingo, one code cleared on the drive home. You're brilliant, and don't sell yourself short; you're a great teacher..
Well, you did it again! You seem to have found the problem. It's maddening how many shops throw parts at the problem and you end up paying for not repairing an issue properly. You are a rare thing Eric.
You're not a good teacher?!?! Nothing could be farther from the truth. You are hands down the best diagnostician/technician/mechanic I've seen, and I have seen quite a few. You do a great job transferring knowledge to those of us out here who are interested in learning. Thank you Eric.
I agree with the last comment, you did a great job on this video and you're not a bad teacher at all! Sometimes I can be a bad listener especially when I'm listening to these videos in my car over Bluetooth but other than that, you're actually a better teacher than you think. I don't know anything about the computer in the scan tool that you were using because I think that's something automotive shops mostly invest in but overall, great video! I'm looking how to not only locate but how to repair a bank 2 sensor, O2 sensor on a 2005 Lexus ES330 I'm having trouble finding one for what specific year, make and model. I don't think the catalytic converter has gone bad yet because it doesn't stop at a certain speed, it's not overheating but it is idling rough at this point, the check engine light came on after I ran out of gas on the highway so the test at AutoZone came back as Bank 1, bank 2, O2 sensor or code P 0420, 0430 which is the bank 1 and bank 2, O2 sensor and they said it was most likely the downstream or bank 2 sensor so I'd like to try to do it myself so that I can save money. The part at AutoZone is around $50 and I have a good family mechanic and now I'm thinking, I should probably just take it to him because you've got me wondering if it could be the air fuel ratio sensor, the one that looks exactly like the O2 sensor but is in fact different which I've heard in several videos and they all say, don't let the auto parts store argue with you, just let them look stupid because they are two different parts and they have two totally different functions. If you do know anything about a 2005 Lexus ES330 and where the bank 2 sensor is located, please please let me know, I will be forever grateful. I watched one video and the guy had to take out his center console and his driver seat in order to get to his bank 2 sensor and if I have to do all that, that's fine if it will save me some money. Common Sense goes a long way and I'm very blessed to have a lot of that LOL, not so many people have that anymore these days LOL. Thanks again for the great video, I've been learning so much from watching these videos, I think it's important to know as much as you can about your vehicle
2001 or 2002 Honda Insight CVT CHECK ENGINE LIGHT ON Scan tool list bank 1 O2 heater circuit quick look at connector, looks ok. Next look at heater signal from ECU and it's delivering voltage to the sensor. Next check at sensor for complete heater circuit ...ahh open circuit. The sensor was an A/F ratio sensor, and oh Momma ! the price was many times more than an O2 sensor...and they do look alike. I'm lucky that I only had a burnt out heater in the sensor ,it was a quick diagnosis. The new A/F Ratio sensor was the fix, and has been going steady ever since ! I want to Thank You for all the time and effort you dedicate to the videos you make. It's sharing the information that makes you the best kind of teacher ! I've worked next to folk who won't share info for fear that I might be a threat to their position or job. That's a tough row to hoe !! I believe we are,. our brothers keepers and to pass on knowledge and educate those new upcoming co workers. I send good thoughts to you and your family !! I hope you have a great Holiday Family Gathering !
If you were local to my area, you would be my preferred premium mechanic...just this one video you demonstrated your aptitude & attitude and pride you take in knowing how to diagnose, troubleshoot and resolve issues. You’re one in a few worth their weight in gold. Thank you for sharing.
Wow, you nailed it. Your voice even perked up when you figured it out. I commend you on your methodical troubleshooting. Finding an incorrect part installed by someone else can be a troubleshooting nightmare. Also, you can use a 1lb propane cylinder with a std torch head to richen up the engine. Squeeze a length of hose on the torch end and put the free end in the air intake. Just crack the valve open and dont ignite the torch. You can fine tune how much added "fuel" you want to send into the engine. Great video, thanks.
So - after watching this awesome demonstration of your diagnostic abilities - one has to ask why the engineers would not engineer a completely different connector so there is no mistake made as to installing an O2 sensor in place of a AFR sensor. GREAT DEMONSTRATION 👍👍. We know that at least one reason engineers design for an AFR sensor - instead do an O2 sensor - IT MAKES THEM MORE MONEY - a better mouse trap ?
This Rav 4 did not set up a DTC code because for the ECU to generate a code it on the AFR system it needs a steady rich or lean condtion failure present for at least 5 seconds but because you had a O2 sensor oscilating between rich and lean in less than that the PCM never set it up. Thank you for your videos.
Trying to understand why the heater resistance showed 0 ohms, which would look like a short. My 2005 Avalon FA heater is 2.6 ohms. But great helpful video.
Yes me too. B1s1 p1135 and p1155 b2s1 2002 xamry just replaced o2...af sensors. Part numbers 2349042, 2349047 denso and the light is still on!!! They ohm test at 3.0 or 2.9ish. I thought that meant they're good as the old ones just stay at 1!!! So lost I'm really losing out here on life. Need a car for a job etc etc etc smh
@Dee-hi5zj it did but I bought new o2 sensors...and it still didn't work UNTIL my mechanic grounded this loose wire. We had no idea where it belonged and in front of my face he Saud fk it and screwed it on to the closest screw it could have came from and voila. I t was upper front engine and a lone wire coming from the chassis. Everything plugged in just fine except that stray wire and he grounded it. It worked
Hey. I know it's an old video. I'm sure you've heard this by now or many people have commented on it but in the video you said you weren't really sure why they went with widebands over standard narrowbands. Basically a narrowband only knows if it's above or below stoich. It doesn't know by how much. That's why it's switching from rich to lean. It doesn't know where stoich is. It has to guess. If it becomes far outside of stoich then it'll ratchet up the short term fuel trims in increments until it gets on the other side of stoich. Then keep switching back and forth to keep as close to stoich as possible. A wideband, on the other hand, KNOWS how far out of stoich it is. So instead of switching back and forth to keep as close to stoich as possible it can do near immediate fuel corrections to keep it at stoich. That's why a wideband data signal will stay flat. Likewise, if it's far outside of stoich it won't have to ratchet the fuel trims to figure out where stoich is. They can do a one shot adjustment. All this means less emissions and less the manufactures have to pay in emission taxes. The number one thing driving vehicle complexity! Great video as always!
Pretty much true. In my honda training they basically said they don't do anything. It was about basically snake oil like air injection. Afr sensors are accurate.
So please correct me if my analogy is wrong. Wideband vs narrowband is like a camera lens. The narrow lens sees a narrow viewing angle, while the wide lens sees a wide viewing angle. So the wideband AFR sensor can "see" the ratio getting out of range and then makes tiny adjustments. The narrowband has to wait until the ratio is way off, then has to make bigger adjustments. Correct? What I am wondering is if bank 1 and bank 2 sensors are interchangable? Could be a good way to diagnose one going bad.
I'm currently working through your videos in order. This is the first "if I can do it you can do it" (albeit a slightly different variation) it is so cool to see your progression from stiff (and slightly awkward, I mean professional 😂) to a relaxed, funny, showing your true talent as a professional. Great work Eric, love your videos.
I'm just glad the "Doctor O" moniker was dropped quickly. I'm sure it seemed like a good idea in the beginning, but that would have quickly become cringy. 🙂
I always enjoy your videos, but they never have been applicable to me yet. The first five minutes of this cleared the situation here up for me immediately. Why was it so hard to see that this configuration of O2 sensors doesn't work like others!? I hadn't seen that elsewhere. I've got +20% LTFT and upstream O2 just sitting up at 0.7 V and couldn't understand what on earth was happening. Thanks for helping me not immediately suspect bad O2 sensors. Checking for vacuum leaks and fuel pressure next. Great stuff!
I know this is an old vid, BUT, thx for posting this! I had a 98 Corolla 1.8 that would not do a complete drive cycle as well, with everything but the 02 monitor and cat monitor not run.. It did run an evap monitor and passed that. Now, I could've sneaked it through with 2 monitors not being set, but I was looking at the customer's past 3 yrs of emissions tests, and found that each time, neither the o2 nor the cat monitor had passed. Based off of what I learned from your posting, I found the car had 2 bad AFR sensors. The pre cat was bouncing around like an O2 sensor, and the post cat was flat lined at 0v, no matter what. No codes, no pending codes. Heater tests passed. After installing the proper AFRs, their monitors ran right away. Before this, the car was running long term fuels of +6%, short term 0. After the repair, the car was -6 and +6, so 0%. Miraculously, the cat passed! Thx to your vid, I got the O2 sensor logic out of my head, and the AFR sensors' proper function in my skull instead! 2 other shops had fixed various evap related problems, but missed the AFR problems. So thanks again! You da man! :) ( Note, I got the car because the customer was also complaining of decreased fuel mileage. We shall see if that problem is fixed )
This is the stuff I need to see the most. I have one foot in the present and the other in 1969 (when I first got a job at a Chevy dealership). I would like to keep up enough to be able to continue doing most of my own work. Chevys from the '50 s and '60 s were a dream to work on and had a ton of interchangeable parts between small blocks. A starter would fit all the small blocks and the 6 cyl.
I've been watching these videos for years. Sometimes they are too in depth, and sometimes off the point. Since I've postponed buying for a 2003 Toyota with the 2.4 engine until I was sure I needed a sensor. Your video came at the right time. Since you stayed on topic it was easier to understand. Thank you.
You taught me. I did all this to my car today, and the AF sensor failed. Had a 1.0 on the ohms for the heater circuit. Did some research and discovered that someone installed a narrow band sensor. Close but no cigar. Explains a lot of issues and the Engine OFF volts jumping up and down. California cars require a Wideband sensor.
I have been having P0138 code meaning high voltage on bank 1 sensor 2 on my toyota corolla. I have literally checked everything I could on the electrical signals ( i have masters in elecrical and computer engineering so I do know what I am doing). Finally changed my o2 sensor but i have been having the same code back and again. And I also checked the graphical reading of the afr sensor and it is showing the exact curve as yours and I think I have found the actual culprit. As the afr sensor is responsible for the actual air fuel mixture and being faulty it has caused the system to run lean. This in turn is causing the error code. I will replace my afr sensor and hopefully it works. Thanks for the actual diagnostic video.
I am enamored by your videos. I hung around my dad fixing just our family's cars growing up and am not afraid to get my hands dirty. I do my own brakes when needed but your videos have definitely shown me I shouldn't attempt my corollas wheel bearings if I ever have to do that. You're a great teacher, contrary to what you say. Your customers must love you and if wasn't 1000 miles away I'd totally bring my cars to you. Keep on doing the great work. What did auto shops work on before emissions controls? It seems like half if your jobs are emissions related.
Christina Kendrick Hey that's pretty cool! Glad you enjoy the videos :) Well the emissions is a love hate really. It is a about a 50 / 50 as far as mechanical vs emission related repairs. NY is tough on the whole check engine light deal so people are forced by the state to fix their cars.
South Main Auto Repair In Illinois only the populated counties have emissions tests (calling it a test is stupid because if the check engine light isn't on, YOU PASS) and only after the car is like 5 years old and then every other year I think. No vehicle inspections here, although we could definitely use them, I see people riding around in literal pieces of garbage all the time. One girl sticks in my head - she was in a RSX and one of the 5 spoke aluminum wheels had significant damage where one of the spokes was even broke and you could see the car wobbling down the road. That's totally safe I'm sure!
Christina Kendrick Lol that sounds scary. We have pretty stick laws here on safety and emissions inspections (once a year) but like anything, give people rule and they will find ways around it. There are plenty of lickem and stickem shops around so we see our fair deal of garbage driving up and down the road too.
A regular o2S indicates only rich or lean, but an AFR sens. indicates HOW RICH or HOW LEAN, that's why the AFR sensor is more accurate, that's what I ahve been learning about them, Eric O
For me, if I only had one a/f, I might not have known there was an issue with the a/r sensor. It did change state but not as much as the working a/r. So that sort of concerns me in that how would a DIY know it was bad. In addition, when we were looking at the two sensors side by side, it wasn't super apparent to me that they were different since the scales did not match. But, I did notice what you observed in that the bad sensor wasn't as stable. Thanks for the video.
Great lesson! I hope the Toyota dealer in question has watched your video. They must feel cheep now! And they must be ashamed of themselves for not fixing correctly one of their own... God Bless. Thanks for posting.
Awesome Video!! One test you could also do is a key on engine off and see if both AFR sensors voltages on scan tool are the same. Just because nothing is going through exhaust and should be at 3.3 or very very close.. Also just note that scan data is the only way to see that voltage change. If you lab scope voltage at connector connected to AFR sensor that the voltage will not change like it does on scanner. Scanner gets its information from the pcm which looks at the amperage and changes that to a voltage on the scan tool. Some even changed it to a normal looking O2 voltage to be easier for the tech.. Thank you for the video I think you're an awesome teacher.
Second view on this video and on a snap throttle the new one has much better numbers. The min- max can be cleared to capture the test results by clearing them before the snap. I love this video because it shows the difference that half of a volt makes and why learning the characteristic views of a known good af is so important. These differences stand out but if you only have a one bank engine you wouldn't know. Capture a min- max on different cars and you will learn different manufacturers known goods. Great video.
Good fix sir. I think there should be a standard to make all AF sensor a special connector and color to differentiate them. Thank God my car has different connectors four pins for the AF sensor and two for o2 sensors.
The use of AFR was Toyota's attempt to bring the points up of the Smog rating on the EPA's green vehicle list. It's wider range provides a more instantaneous corrective response to the load changes on the engine. They started to use it back in 1997 on the California released models.
awesome video.... never occurred to me until you mentioned was to consider in what order the monitors set. gives a direction as far as a diagnosis when no codes are present and monitors not setting
Great video Eric, amazing how toyota factory trained technicians replaced computers and other parts and didn't think to monitor the AF sensors. In addition during check mode you can confirm the sequence of sensors checked and that need to pass to complete the drive cycle. Amazes me Toyota techs aren't aware to perform this procedure. Eric what is it you think lacks in training their Techs ? Some dealerships go the extra effort for more tech training and some do not ?? Really, unbelievable. Thanks again great video.
Excellent as always!!! A wideband is used whenever a manufacturer needs the vehicle to operate in very lean mode (stratified combustion), in certain conditions to save on fuel. In which case (stratified mode) the normal O2 sensor would be stuck on lean, and would not be able to give a reading, as opposed to the AFR sensor which can give the exact "AFR" to adjust accordingly. Cheers!
+Nabil Chouchany i think you are wrong!, because the stratified mode is only use on direct injection only!, this AFR sensor are use because they are capable of sensing not only if is lean or rich, also how much lean or reach is, are more exact then O2 sensor!
+Miguel espinal Méndez I was wrong in the sense that Eric O did mention what i said in the video... i was hasty with my comment, did not wait for the video to end. But lean mode is used on Vtec and other systems (not necessarily direct injection). And yes, they are more exact, or at least they provide a direct measure, compared to a 2 step O2 sensor.
Miguel espinal Méndez Dear Sir, what I only know "very lean condition always is a potential reason of generating Pollution", so more precise +/- calibration of Stoichiometric 14.7:1 is purpose of AFR Sensor.
AFR sensor will tell the PCM exactly how lean nor rich the engine is running so more accurate adjustments can be made. O2 sensor would only show a lean or rich condition and the PCM had to spend more time correcting the mixture. Hope this helps.
Nice video. I noticed the y-axis' were different on your scanner for the two sensors especially before you replaced the sensor. B2-S1 was in a very narrow range (3.03 - 3.47) which would magnify any changes while B1-S1 was in a broad range (2 - 4.15) - this would compress the peaks and valleys and make it look more steady. It would be easier to compare them if they were in the same range, not sure if the software can do that. Very informative. When my 02 Camry was throwing an O2/AFR code it took me quite a while to figure out the difference between the two and if there really was one. Replaced the upstream AFR sensor and it still threw a code, replaced the downstream O2 and so far so go 2 years later.
That's a good observation. Most people would not have picked up on that. If I was watching that on the lab scope as opposed to just scan tool data I could have set my min and max Vdc on the y-axis. However when you graph data on the scan tool it sets its own min and max based on what it captures, so all I can do is force it rich then lean and it is what it is at that point as far as low and peak values, but this could trick some one for sure. That is one reason I tell people to look at the numbers not just the picture ;) As I mentioned in the video this is the best way to test AFR's. I would have loved to show the data on a lab scope but they are tricky to do like that. I really just wanted to fix it lol. Going to see if it will run a drive cycle today, got my fingers crossed!
I know I watched a video of the 3 steps to fixing something on Ave's channel and one of them is don't trust the last mechanics word. I couldn't tell you how true that is! great vid eric!
Good day mr i have a 4x4 2000 toyota tundra v6 5vz-fe.The mileage is high but woked fine until one morning it started idling low puffs black smoke all plugs keep fouling bad smell in exhaust jurking when mild accelerating and cut off twice one time different days.No check engine light and no hard starting.Please help i live in the caribbean thanks and take care.
the conventional oxygen sensor is characterized by a sudden change in its output voltage at the threshold of the stoichiometric air fuel ratio (14.7:1). In contrast, the air fuel ratio sensor data is approximately proportionate to the existing air fuel ratio. The air fuel ratio sensor converts the oxygen density to current and sends it to the ECM. As a result, the detection precision of the air fuel ratio has been improved.
You have a future in the classroom. You should go teach at a trade school. I have learned a lot just by watch you. There a lot of stuff they don't teach in tech school or just give you the basic. You have help me learn the rest. Thanks
nice job Eric .Why can,t all mechanics follow your lead it should be compulsory every garage owner have s video of your good self showing them what's what.if only lol.good video.
Good job boss ... I just stared my career 1 year ago I love to make things work and change only what needs to be change ... I been watching your videos and your really good .. Keep it up my blessing for you
Good for you david cisneros ! What kind of shop are you working in? Dealer, franchise, self employed , independent? Just remember we can't know everything, don't throw tools, walk away and breath, pay day's on Friday and don't bite your finer nails haha those are my words of advice for you. No just kidding, I hope you exceed in your career and like I mentioned in the video, if I can do so can you!
I'm working in a shop now ... Im not realy making $$$ but it's ok I also went to school for 1 year free of course, I going to continue with school as soon as I can afford it it's not free any more hahha so I saving some money to keep going so in in the meantime you guys are my teachers ...Thanks to all you guys .... I appreciate it
I still wish there was a way to measure the current on Fuel Ratio sensors directly. I know they are better because they can detect lack of fuel (or to much) rather than just the amount of oxegen, but I don't like it. I fear change. 100/450/900 Forever!
Toyota made the same connector for both O2 sensor and AF ratio sensor. Camrys equipped with this engine can have either sensor....depending on if it is calif. Or federal car. We always have to look at the part number on the sensor when replacing it. ......and we were working at the dealership at the time.
Well Done! Love it. As a EE, I am most impressed with your knowledge and actions. Plus you do a fine job of SHOWING and EXPLAINING things! On my own 2003 Lexus RX300, I had a code for B2 S1 AFR. $125 for a Denso. Change other one, Plus O2 $50 for Denso for preventive maint.
Thank you for this video. Going to perform these lean/rich tests on my 96,000 mile 2005 V6 Toyota Camry a/f sensors tomorrow. I suspect one of my a/f sensors is lazy since my idle is slightly bouncing.
Thanks, Eric! Have an 08 Tacoma that sets CEL on acceleration over 3k rpm only. Takes several drive cycles to clear it. Went after O2 sensor then Toyota dealer was asked why only on heavy acceleration and they said AFR. If there are two as it seems this RAV did, I need to determine which one as you did. Thanks, again!
I had a similar problem to yours only it had a sensor fault code for B1 s1.(forget the exact description) The customer had installed his own sensor (From E-Bay) and the scope displayed a pattern for an O2 sensor instead of an A/F sensor only the voltages were different. The connector was identical also. Replaced with the correct part..problem solved. Nice diagnostics by the way.
Hey thanks wysetech2000! Yeah it was pretty interesting huh. I thought the crazy part was the fact he has driven it sense Aug. 1000's of mile and no codes and no drive cycle. Install correct AFR now it will run the monitor in 2 miles... just when you think you've seen it all.
wysetech2000 Yeah we get a lot of the rejects at our shop. Mostly referrals from other shops. Always good for customer relations too. Usually builds a lifetime customer.
Educational Video , and your right an OBD II code reader will show almost a flat line display for the A/F sensors. Know you are swamped with questions but do you think hooking up a Tektronix oscilloscope will let me actually view the waveform. Thinking of pulling the trigger on a Snap-On scanner . Thank you.
I am not to sure how the dealership missed this. I know there are some bulletins out for this car, for Cats and ECM's with oxygen sensor and cat codes, but this is pretty cut and dry. Nice work.
+Hannah Belk no kidding! In my opinion there is no reason a make specific dealership should have missed this! Can't imagine how much the owner spent on parts going off uneducated guesses from other mechanics! ERIC'S THE MAN!!!
Want to let you know I appreciate your videos. Very methodical approach. Do you think it was possible one of the previous people working on this vehicle put an a o2 sensor instead of a/f sensor.
Wow -- excellent work and amazing expertise! I wish I could find a mechanic as competent as you in my area!! Whatever your boss is paying you, he should double it -- seriously. Where else is a person going to find a mechanic as thorough, knowledgeable, and concerned about the customer? Mechanics of this caliber are EXTREMELY hard to come by -- I'm not joking. Maybe you can do a video on how people can find a good repair shops in their area. There's just so much incompetence out there it's insane -- even at dealerships. Or should I say, ESPECIALLY at dealerships (in my experience). I don't particularly enjoy working on cars, but do as much of my own stuff as possible just because I've had many things damaged by gross negligence and incompetence. I've lost a lot of trust -- not that I'm going to get ripped off, just don't trust people will actually do a good job.
Well thank you! Thanks for watching too. I wasn't sure if any one would wanna watch a 30min video of me rambling about a AFR lol. And my boss paying me haha I wish lol. I own the shop so I don't even get a pay check. Customer satisfaction and not working for a boss (the man) is my pay. I don't really consider myself high caliber. As a matter of fact I am not ASE or ABC, or LMNOP or any other fancy acronym. I never went to collage, and as far as that goes I barley made it through high school. I grew up in my mom and dads shop and learned how to treat customers, run a business, work hard and do the best job you can. It is sad that we can't find mechanics who give a darn or want to do the best they can to help. It seems any more they just wanna play grab ass with there service writer, get the best pay flat rate jobs on the tickets and change parts then go home and drink beer... me, well I just have a desire to know how and why things work. Been that way sense I was a kid. Love seeing things work. As far as the dealership guys that is to bad. They have all that training at there finger tips and access to the best of everything for free, yet they just goof around and bounce job to job and don't really care. There pay scale drives them that way. They get paid on flat rate. It's all about turning hours, it really sucks for the customer though. No personal service, no talking to the tech. Just go go go or get fired. Any how I can ramble on that for ever. Thanks again for subscribing and watching!
Being cheap will sometime cost you more than taking a problem to the dealer - but we don't know how much other shops have charged or if they fixed problems not related to this error. Many have told me don't lift the hood until you have a problem which means little or no maintenance.
so this mystery is solved... new parts, correct or not can make others shoot off that parts cannon in a heart beat. toyota and lexus a/fr's will have a colored tape band around them, which toyota if ordered through them will be needed when replaced. unsure why, however a good quality correct denso part tends to do the job very well for most application from my experience. denso only has a failure rate of less than 1/2 of one percent, unless you are speaking of denso parts installed from the factory on a dodge. good find and good info
Great video. I think Pico has got some information about air fuel ratio sensors in database and some sample specimen traces? Good to upload traces of good and bad components for the information and learning database. Never ceases to amaze me they do this for free. I know their kit ain't cheap but so worth it for what buying in to.
The advantage of a V engine is you have two of each type of A/F sensors and oxygen sensors. This allows you to compare waveforms. With only one of each type like on an inline engine, it is possible to miss this problem.
Eric, thanks for the help. I have a Toyota Sienna 2007 , though in my case, if I run at idle, AFS stays at 3.29 like in your case but when I accelerate and stop, it will drop all the way to zero and it will slowly ramp up to 3.29, only one time I saw it stay below 3 on one of them but it came back after the second throttle. I was watching the Long and short terms, when it is at idle, I see 7.XX & 10.XX (Long FT), when I accelerate and keep it, it stays at around 3 for both of them, when I accelerate just a little bit and keep it, it stays 4 & 7; the change is instant. I was thinking of a vacuum or bad data from the MAF but when I accelerate and decelerate, I see the MAF responding very well. The reason I'm concerned about the AFS is because at some point I did have a code on it but I would reset it and it would not come back until several months later. I did notice that the exhaust gets a little hotter over time because I can hear the cooling down noise lol. Please let me know what you think in this case. I currently have no codes stored.
4 exhaust sensors on a 4-banger...never seen that before! Bank1 and Bank2 were confusing at first; had to look up the layout on AllData to satisfy the curiosity haha
I know this is old but how does Toyota explain the nomenclature convention? Bank 2?? I guess they designed the fuel metering algorithm to be modular and adaptable their multi bank systems. Where was the other primary sensor?
At 14:03 both values are about the same. The reason the left one looks to be bouncing is because the y-axis scale goes from 3.03 to 3.47, whereas the right one has a y-axis scale that goes from 2.00 to 4.15. Noticed the changed y-axis setting at 19:30, after the installation of the new O2 sensor. Why was this done?
Excellent diagnosis friend. I can see why the readings of the o2 sensor used as the AF sensor, would be all over the place, because of the way in which the two of them work are completely opposite. An A/F sensor, or Wide Band sensor, has more range, more precise readings. Although where they differ more so, is that an A/F sensor, unlike the o2 sensor, puts out a higher voltage reading as it becomes Rich, and lower voltage when reading Lean mixtures. (just the opposite of an O2 sensor.) So, I am more than curious if in fact, your diagnosis, and repair corrected the vehicle's ability to "run a drive cycle" Did it? Thank You.
Ha I was just letting RUclips play videos for me and this came across. I fixed an 02 Avalon for this same problem yesterday. Only complaint was an abnormal shift.
A bad teacher is one who can't impart knowledge to his or her students. A good teacher is one that can explain a problem and a solution to the problem. In this video, I would rate you as a GREAT teacher.
Finally I found a video showing what these stupid widebands should look like and read on a scan tool! I swear this is the only video on RUclips that actually shows it! Thank you so much! I'm in the middle of diagnosing a 5 wire sensor on a buddy's car and now I can be confident that it's faulty and needs replacing! Thanks a lot again sir! Great video!
Just found this gem after watching 100s of newer videos. I understood everything you were explaining and enjoy your in depth analysis. I have no clue if I will ever use it in my lifetime....
I learned so much from your video. Most importantly...The front sensor is NOT an O2 sensor but a air/fuel ratio sensor!!! I was about to change this sensor on my buddy's 03 Tundra as my scan tool gave me flat line readings and not a sine wave. Turns out, this is normal. You saved my friend $180 because that is what the Denso part cost. Took me half dozen YT vids to find the one that gave me the right answer and that was this video. Thank you!
As a apprentice I’ve learned the ppl that say they cant teach are usually the brightest teachers 👨🏫 I enjoyed the diag. Thanks Eric.
Eric, my understating is that when you're reading an AFR signal in OBD II mode, you get 1/5 the value of the AFR reading in Enhanced MODE. Therefore, if the Enhance mode reading of the AFR sensor is 3.3 Volts, in OBD II mode you will read the AFR Voltage as 0.666 V which equals 3.3v/5v = 0.66 Volts, in addition during acceleration in OBD II mode, the AFR signal in OBD II value will display about 0.5 V, which equals a AFR Voltage (enhanced mode) of 2.5 V (equals rich mixture); therefore 2.5 V/5V = 0.5 Volts. Also, as you mentioned, further testing and confirming the AFR sensor is operating correctly, you could remove the harness side connector of the AFR sensor, put the probes of a VOM or a Scope between the two signal wires of the AFR sensor (while AFR sensor is still in exhaust pipe) , jump the two heater wires from the disconnected Harness connector to the heater wires on the AFR sensor heater wires ( helps keep the AFR sensor at optimum Temp while conducting this test) , you will get an Analog signal ranging from about 0.8 V to about 0.2 V just like a Narrow Band O2 sensor. This confirms the correct operation of the AFR sensor if you do not have the ability to Read Enhanced mode data. Thanks for the great video!!! What Amazes me is how is it an ASE Certified Toyota Dealership Tech could not identify and confirm a faulty operation of this AFR sensor, Amazing !!!!!!!!!!
2006 Toyota Camry. Drive cycle wouldn't complete 3 months. Changed the Air Fuel Regulator in the CAT. bingo, one code cleared on the drive home. You're brilliant, and don't sell yourself short; you're a great teacher..
Well, you did it again! You seem to have found the problem. It's maddening how many shops throw parts at the problem and you end up paying for not repairing an issue properly. You are a rare thing Eric.
You're not a good teacher?!?! Nothing could be farther from the truth. You are hands down the best diagnostician/technician/mechanic I've seen, and I have seen quite a few. You do a great job transferring knowledge to those of us out here who are interested in learning. Thank you Eric.
I agree with the last comment, you did a great job on this video and you're not a bad teacher at all! Sometimes I can be a bad listener especially when I'm listening to these videos in my car over Bluetooth but other than that, you're actually a better teacher than you think. I don't know anything about the computer in the scan tool that you were using because I think that's something automotive shops mostly invest in but overall, great video! I'm looking how to not only locate but how to repair a bank 2 sensor, O2 sensor on a 2005 Lexus ES330 I'm having trouble finding one for what specific year, make and model. I don't think the catalytic converter has gone bad yet because it doesn't stop at a certain speed, it's not overheating but it is idling rough at this point, the check engine light came on after I ran out of gas on the highway so the test at AutoZone came back as Bank 1, bank 2, O2 sensor or code P 0420, 0430 which is the bank 1 and bank 2, O2 sensor and they said it was most likely the downstream or bank 2 sensor so I'd like to try to do it myself so that I can save money. The part at AutoZone is around $50 and I have a good family mechanic and now I'm thinking, I should probably just take it to him because you've got me wondering if it could be the air fuel ratio sensor, the one that looks exactly like the O2 sensor but is in fact different which I've heard in several videos and they all say, don't let the auto parts store argue with you, just let them look stupid because they are two different parts and they have two totally different functions. If you do know anything about a 2005 Lexus ES330 and where the bank 2 sensor is located, please please let me know, I will be forever grateful. I watched one video and the guy had to take out his center console and his driver seat in order to get to his bank 2 sensor and if I have to do all that, that's fine if it will save me some money. Common Sense goes a long way and I'm very blessed to have a lot of that LOL, not so many people have that anymore these days LOL. Thanks again for the great video, I've been learning so much from watching these videos, I think it's important to know as much as you can about your vehicle
2001 or 2002 Honda Insight CVT
CHECK ENGINE LIGHT ON
Scan tool list bank 1 O2 heater circuit
quick look at connector, looks ok.
Next look at heater signal from ECU and it's delivering voltage to the sensor.
Next check at sensor for complete heater circuit ...ahh open circuit.
The sensor was an A/F ratio sensor, and oh Momma ! the price was many times more than an O2 sensor...and they do look alike.
I'm lucky that I only had a burnt out heater in the sensor ,it was a quick diagnosis.
The new A/F Ratio sensor was the fix, and has been going steady ever since !
I want to Thank You for all the time and effort you dedicate to the videos you make. It's sharing the information that makes you the best kind of teacher !
I've worked next to folk who won't share info for fear that I might be a threat to their position or job. That's a tough row to hoe !!
I believe we are,. our brothers keepers and to pass on knowledge and educate those new upcoming co workers.
I send good thoughts to you and your family !! I hope you have a great Holiday Family Gathering !
If you were local to my area, you would be my preferred premium mechanic...just this one video you demonstrated your aptitude & attitude and pride you take in knowing how to diagnose, troubleshoot and resolve issues. You’re one in a few worth their weight in gold. Thank you for sharing.
You are so right about that teacher Erick
Wow, you nailed it. Your voice even perked up when you figured it out. I commend you on your methodical troubleshooting. Finding an incorrect part installed by someone else can be a troubleshooting nightmare.
Also, you can use a 1lb propane cylinder with a std torch head to richen up the engine. Squeeze a length of hose on the torch end and put the free end in the air intake. Just crack the valve open and dont ignite the torch. You can fine tune how much added "fuel" you want to send into the engine. Great video, thanks.
So - after watching this awesome demonstration of your diagnostic abilities - one has to ask why the engineers would not engineer a completely different connector so there is no mistake made as to installing an O2 sensor in place of a AFR sensor. GREAT DEMONSTRATION 👍👍. We know that at least one reason engineers design for an AFR sensor - instead do an O2 sensor - IT MAKES THEM MORE MONEY - a better mouse trap ?
This Rav 4 did not set up a DTC code because for the ECU to generate a code it on the AFR system it needs a steady rich or lean condtion failure present for at least 5 seconds but because you had a O2 sensor oscilating between rich and lean in less than that the PCM never set it up. Thank you for your videos.
I have an 02 Camry & you just taught me where I screwed up. Thanks. Had no idea there was any difference between the up & downstream sensors.
Thanks for this video. After watching this video, I understood how the sensors worked and was able to fix my problem.
Trying to understand why the heater resistance showed 0 ohms, which would look like a short. My 2005 Avalon FA heater is 2.6 ohms. But great helpful video.
Yes me too.
B1s1 p1135 and p1155 b2s1 2002 xamry just replaced o2...af sensors. Part numbers 2349042, 2349047 denso and the light is still on!!!
They ohm test at 3.0 or 2.9ish. I thought that meant they're good as the old ones just stay at 1!!! So lost I'm really losing out here on life. Need a car for a job etc etc etc smh
@@samaelmartinus3273 Did the problem resolve? I'm facing same with exact car.
@Dee-hi5zj it did but I bought new o2 sensors...and it still didn't work UNTIL my mechanic grounded this loose wire. We had no idea where it belonged and in front of my face he Saud fk it and screwed it on to the closest screw it could have came from and voila. I t was upper front engine and a lone wire coming from the chassis. Everything plugged in just fine except that stray wire and he grounded it. It worked
Hey. I know it's an old video. I'm sure you've heard this by now or many people have commented on it but in the video you said you weren't really sure why they went with widebands over standard narrowbands.
Basically a narrowband only knows if it's above or below stoich. It doesn't know by how much. That's why it's switching from rich to lean. It doesn't know where stoich is. It has to guess. If it becomes far outside of stoich then it'll ratchet up the short term fuel trims in increments until it gets on the other side of stoich. Then keep switching back and forth to keep as close to stoich as possible.
A wideband, on the other hand, KNOWS how far out of stoich it is. So instead of switching back and forth to keep as close to stoich as possible it can do near immediate fuel corrections to keep it at stoich. That's why a wideband data signal will stay flat. Likewise, if it's far outside of stoich it won't have to ratchet the fuel trims to figure out where stoich is. They can do a one shot adjustment.
All this means less emissions and less the manufactures have to pay in emission taxes. The number one thing driving vehicle complexity!
Great video as always!
Great explanation.
Now I know why 😜
There always a logic to this madness
Pretty much true. In my honda training they basically said they don't do anything. It was about basically snake oil like air injection. Afr sensors are accurate.
So please correct me if my analogy is wrong. Wideband vs narrowband is like a camera lens. The narrow lens sees a narrow viewing angle, while the wide lens sees a wide viewing angle. So the wideband AFR sensor can "see" the ratio getting out of range and then makes tiny adjustments. The narrowband has to wait until the ratio is way off, then has to make bigger adjustments. Correct? What I am wondering is if bank 1 and bank 2 sensors are interchangable? Could be a good way to diagnose one going bad.
I'm currently working through your videos in order. This is the first "if I can do it you can do it" (albeit a slightly different variation) it is so cool to see your progression from stiff (and slightly awkward, I mean professional 😂) to a relaxed, funny, showing your true talent as a professional. Great work Eric, love your videos.
I'm just glad the "Doctor O" moniker was dropped quickly. I'm sure it seemed like a good idea in the beginning, but that would have quickly become cringy. 🙂
I always enjoy your videos, but they never have been applicable to me yet. The first five minutes of this cleared the situation here up for me immediately. Why was it so hard to see that this configuration of O2 sensors doesn't work like others!? I hadn't seen that elsewhere. I've got +20% LTFT and upstream O2 just sitting up at 0.7 V and couldn't understand what on earth was happening. Thanks for helping me not immediately suspect bad O2 sensors. Checking for vacuum leaks and fuel pressure next. Great stuff!
I know this is an old vid, BUT, thx for posting this! I had a 98 Corolla 1.8 that would not do a complete drive cycle as well, with everything but the 02 monitor and cat monitor not run.. It did run an evap monitor and passed that. Now, I could've sneaked it through with 2 monitors not being set, but I was looking at the customer's past 3 yrs of emissions tests, and found that each time, neither the o2 nor the cat monitor had passed. Based off of what I learned from your posting, I found the car had 2 bad AFR sensors. The pre cat was bouncing around like an O2 sensor, and the post cat was flat lined at 0v, no matter what. No codes, no pending codes. Heater tests passed. After installing the proper AFRs, their monitors ran right away. Before this, the car was running long term fuels of +6%, short term 0. After the repair, the car was -6 and +6, so 0%. Miraculously, the cat passed! Thx to your vid, I got the O2 sensor logic out of my head, and the AFR sensors' proper function in my skull instead! 2 other shops had fixed various evap related problems, but missed the AFR problems. So thanks again! You da man! :) ( Note, I got the car because the customer was also complaining of decreased fuel mileage. We shall see if that problem is fixed )
This is the stuff I need to see the most. I have one foot in the present and the other in 1969 (when I first got a job at a Chevy dealership). I would like to keep up enough to be able to continue doing most of my own work. Chevys from the '50 s and '60 s were a dream to work on and had a ton of interchangeable parts between small blocks. A starter would fit all the small blocks and the 6 cyl.
dan andy Oh man those days are long gone, seems if you need a starter for a late model GM there is 10 options for each engine haha
Great video Eric, 3 years later I am reviewing it because I have to go diag a Yota AFR tonight!
I've been watching these videos for years. Sometimes they are too in depth, and sometimes off the point. Since I've postponed buying for a 2003 Toyota with the 2.4 engine until I was sure I needed a sensor. Your video came at the right time. Since you stayed on topic it was easier to understand. Thank you.
You taught me. I did all this to my car today, and the AF sensor failed. Had a 1.0 on the ohms for the heater circuit. Did some research and discovered that someone installed a narrow band sensor. Close but no cigar. Explains a lot of issues and the Engine OFF volts jumping up and down. California cars require a Wideband sensor.
I have been having P0138 code meaning high voltage on bank 1 sensor 2 on my toyota corolla. I have literally checked everything I could on the electrical signals ( i have masters in elecrical and computer engineering so I do know what I am doing). Finally changed my o2 sensor but i have been having the same code back and again. And I also checked the graphical reading of the afr sensor and it is showing the exact curve as yours and I think I have found the actual culprit. As the afr sensor is responsible for the actual air fuel mixture and being faulty it has caused the system to run lean. This in turn is causing the error code. I will replace my afr sensor and hopefully it works. Thanks for the actual diagnostic video.
i have been struggling with those just found this video helps a lot
I am enamored by your videos. I hung around my dad fixing just our family's cars growing up and am not afraid to get my hands dirty. I do my own brakes when needed but your videos have definitely shown me I shouldn't attempt my corollas wheel bearings if I ever have to do that. You're a great teacher, contrary to what you say. Your customers must love you and if wasn't 1000 miles away I'd totally bring my cars to you. Keep on doing the great work. What did auto shops work on before emissions controls? It seems like half if your jobs are emissions related.
Christina Kendrick Hey that's pretty cool! Glad you enjoy the videos :) Well the emissions is a love hate really. It is a about a 50 / 50 as far as mechanical vs emission related repairs. NY is tough on the whole check engine light deal so people are forced by the state to fix their cars.
South Main Auto Repair In Illinois only the populated counties have emissions tests (calling it a test is stupid because if the check engine light isn't on, YOU PASS) and only after the car is like 5 years old and then every other year I think. No vehicle inspections here, although we could definitely use them, I see people riding around in literal pieces of garbage all the time. One girl sticks in my head - she was in a RSX and one of the 5 spoke aluminum wheels had significant damage where one of the spokes was even broke and you could see the car wobbling down the road. That's totally safe I'm sure!
Christina Kendrick Lol that sounds scary. We have pretty stick laws here on safety and emissions inspections (once a year) but like anything, give people rule and they will find ways around it. There are plenty of lickem and stickem shops around so we see our fair deal of garbage driving up and down the road too.
A regular o2S indicates only rich or lean, but an AFR sens. indicates HOW RICH or HOW LEAN, that's why the AFR sensor is more accurate, that's what I ahve been learning about them, Eric O
For me, if I only had one a/f, I might not have known there was an issue with the a/r sensor. It did change state but not as much as the working a/r. So that sort of concerns me in that how would a DIY know it was bad.
In addition, when we were looking at the two sensors side by side, it wasn't super apparent to me that they were different since the scales did not match. But, I did notice what you observed in that the bad sensor wasn't as stable.
Thanks for the video.
Really enjoy the analytics Eric. Makes the gray matter work a little harder to stay with you. Good job on this video.....
I've pressed the brake pedal on booster type vehicles to watch the O² sensors react to lean conditions. Has worked pretty good so far.
I’ve had leaking brake boosters cause a lean condition and that’s how to find them.
These early videos man 😂. Good to see how you have grown as a content maker. How much I love the “Welcome to South Main Auto” on the newer videos.
Great lesson! I hope the Toyota dealer in question has watched your video. They must feel cheep now! And they must be ashamed of themselves for not fixing correctly one of their own...
God Bless.
Thanks for posting.
The worst techs I worked with were at dealers. Flat rate makes them even worse.
Awesome Video!! One test you could also do is a key on engine off and see if both AFR sensors voltages on scan tool are the same. Just because nothing is going through exhaust and should be at 3.3 or very very close.. Also just note that scan data is the only way to see that voltage change. If you lab scope voltage at connector connected to AFR sensor that the voltage will not change like it does on scanner. Scanner gets its information from the pcm which looks at the amperage and changes that to a voltage on the scan tool. Some even changed it to a normal looking O2 voltage to be easier for the tech.. Thank you for the video I think you're an awesome teacher.
the sensor has to reach operating temperature 1200 to 1500 F before you can start the rich / lean test to assess the performance of the A/F R sensor.
Second view on this video and on a snap throttle the new one has much better numbers. The min- max can be cleared to capture the test results by clearing them before the snap. I love this video because it shows the difference that half of a volt makes and why learning the characteristic views of a known good af is so important. These differences stand out but if you only have a one bank engine you wouldn't know. Capture a min- max on different cars and you will learn different manufacturers known goods. Great video.
I watched this two years ago and just watched it again after viewing the Wells presentation. Well done sir!
Good fix sir. I think there should be a standard to make all AF sensor a special connector and color to differentiate them. Thank God my car has different connectors four pins for the AF sensor and two for o2 sensors.
The use of AFR was Toyota's attempt to bring the points up of the Smog rating on the EPA's green vehicle list. It's wider range provides a more instantaneous corrective response to the load changes on the engine. They started to use it back in 1997 on the California released models.
Love these old teaching videos. The 2024 vids are great but I love to get more in depth!
awesome video.... never occurred to me until you mentioned was to consider in what order the monitors set. gives a direction as far as a diagnosis when no codes are present and monitors not setting
Great video Eric, amazing how toyota factory trained technicians replaced computers and other parts and didn't think to monitor the AF sensors. In addition during check mode you can confirm the sequence of sensors checked and that need to pass to complete the drive cycle. Amazes me Toyota techs aren't aware to perform this procedure. Eric what is it you think lacks in training their Techs ? Some dealerships go the extra effort for more tech training and some do not ?? Really, unbelievable. Thanks again great video.
Very well done. I would never wear a ring or watch or anything else that could get caught and suck me in.
Excellent as always!!! A wideband is used whenever a manufacturer needs the vehicle to operate in very lean mode (stratified combustion), in certain conditions to save on fuel. In which case (stratified mode) the normal O2 sensor would be stuck on lean, and would not be able to give a reading, as opposed to the AFR sensor which can give the exact "AFR" to adjust accordingly.
Cheers!
+Nabil Chouchany i think you are wrong!, because the stratified mode is only use on direct injection only!, this AFR sensor are use because they are capable of sensing not only if is lean or rich, also how much lean or reach is, are more exact then O2 sensor!
+Miguel espinal Méndez I was wrong in the sense that Eric O did mention what i said in the video... i was hasty with my comment, did not wait for the video to end. But lean mode is used on Vtec and other systems (not necessarily direct injection). And yes, they are more exact, or at least they provide a direct measure, compared to a 2 step O2 sensor.
Miguel espinal Méndez Dear Sir, what I only know "very lean condition always is a potential reason of generating Pollution", so more precise +/- calibration of Stoichiometric 14.7:1 is purpose of AFR Sensor.
AFR sensor will tell the PCM exactly how lean nor rich the engine is running so more accurate adjustments can be made. O2 sensor would only show a lean or rich condition and the PCM had to spend more time correcting the mixture. Hope this helps.
This guy does good work man. Attention to detail is always the key.
Nice video. I noticed the y-axis' were different on your scanner for the two sensors especially before you replaced the sensor. B2-S1 was in a very narrow range (3.03 - 3.47) which would magnify any changes while B1-S1 was in a broad range (2 - 4.15) - this would compress the peaks and valleys and make it look more steady. It would be easier to compare them if they were in the same range, not sure if the software can do that.
Very informative. When my 02 Camry was throwing an O2/AFR code it took me quite a while to figure out the difference between the two and if there really was one. Replaced the upstream AFR sensor and it still threw a code, replaced the downstream O2 and so far so go 2 years later.
That's a good observation. Most people would not have picked up on that. If I was watching that on the lab scope as opposed to just scan tool data I could have set my min and max Vdc on the y-axis. However when you graph data on the scan tool it sets its own min and max based on what it captures, so all I can do is force it rich then lean and it is what it is at that point as far as low and peak values, but this could trick some one for sure. That is one reason I tell people to look at the numbers not just the picture ;) As I mentioned in the video this is the best way to test AFR's. I would have loved to show the data on a lab scope but they are tricky to do like that. I really just wanted to fix it lol. Going to see if it will run a drive cycle today, got my fingers crossed!
I watched this looking for O2 answers. I watch the channel every day and learn something new. Thank you for all the solutions. jim
I know I watched a video of the 3 steps to fixing something on Ave's channel and one of them is don't trust the last mechanics word. I couldn't tell you how true that is! great vid eric!
+drvnucrzy Haha so true!
01 Toyota Tacoma p1135 code
Good day mr i have a 4x4 2000 toyota tundra v6 5vz-fe.The mileage is high but woked fine until one morning it started idling low puffs black smoke all plugs keep fouling bad smell in exhaust jurking when mild accelerating and cut off twice one time different days.No check engine light and no hard starting.Please help i live in the caribbean thanks and take care.
the conventional oxygen sensor is characterized by a sudden change in
its output voltage at the threshold of the stoichiometric air fuel ratio
(14.7:1). In contrast, the air fuel ratio sensor data is approximately
proportionate to the existing air fuel ratio. The air fuel ratio sensor
converts the oxygen density to current and sends it to the ECM. As a
result, the detection precision of the air fuel ratio has been improved.
You have a future in the classroom. You should go teach at a trade school. I have learned a lot just by watch you. There a lot of stuff they don't teach in tech school or just give you the basic. You have help me learn the rest. Thanks
Awesome video Eric! Find the evidence and fix the problem. We're constantly learning in this field.
nice job Eric .Why can,t all mechanics follow your lead it should be compulsory every garage owner have s video of your good self showing them what's what.if only lol.good video.
Good job boss ... I just stared my career 1 year ago I love to make things work and change only what needs to be change ... I been watching your videos and your really good .. Keep it up my blessing for you
Good for you david cisneros ! What kind of shop are you working in? Dealer, franchise, self employed , independent? Just remember we can't know everything, don't throw tools, walk away and breath, pay day's on Friday and don't bite your finer nails haha those are my words of advice for you. No just kidding, I hope you exceed in your career and like I mentioned in the video, if I can do so can you!
I'm working in a shop now ... Im not realy making $$$ but it's ok I also went to school for 1 year free of course, I going to continue with school as soon as I can afford it it's not free any more hahha so I saving some money to keep going so in in the meantime you guys are my teachers ...Thanks to all you guys .... I appreciate it
Glad to hear that david cisneros ! I hope you can gain knowledge from my videos! Stick with it!
Hot tip, (pun intended): An "ove glove" is very useful in these situations. And, as usual, an amazing bit of investigatory prowess. Bravo! :)
Where do spray the solvent? Into the vacuum hose from the purge solenoid? Elsewhere? Excellent video and explanation though.
I still wish there was a way to measure the current on Fuel Ratio sensors directly. I know they are better because they can detect lack of fuel (or to much) rather than just the amount of oxegen, but I don't like it. I fear change. 100/450/900 Forever!
Toyota made the same connector for both O2 sensor and AF ratio sensor. Camrys equipped with this engine can have either sensor....depending on if it is calif. Or federal car. We always have to look at the part number on the sensor when replacing it. ......and we were working at the dealership at the time.
Well Done! Love it. As a EE, I am most impressed with your knowledge and actions. Plus you do a fine job of SHOWING and EXPLAINING things! On my own 2003 Lexus RX300, I had a code for B2 S1 AFR. $125 for a Denso. Change other one, Plus O2 $50 for Denso for preventive maint.
Wheather or not ( YOUR A GREAT INVESTAGATOR ) Like Columbo the detective... You rate at least 999.9 Points in my book....
Thank you for this video. Going to perform these lean/rich tests on my 96,000 mile 2005 V6 Toyota Camry a/f sensors tomorrow. I suspect one of my a/f sensors is lazy since my idle is slightly bouncing.
Just watching this one for the first time today and yes you are a good teacher! Also pretty crazy that this 4 cylinder engine has 4 AFR/O2 sensors.
You can now get a 4 wire sensors which works the same way as a 5 wire sensor so be careful things can get very confusing .
i ve heard about lambda sensors wide band narrow band you never mentioned any of that
easy to understand i loved your video
greetings from Mexico.
Thanks, Eric! Have an 08 Tacoma that sets CEL on acceleration over 3k rpm only. Takes several drive cycles to clear it. Went after O2 sensor then Toyota dealer was asked why only on heavy acceleration and they said AFR. If there are two as it seems this RAV did, I need to determine which one as you did. Thanks, again!
Sometimes I feel good at diagnosing issues, but I hope one day I can get this good at doing so. Great Video!
Great video but the suspense is killing me, did it pass the drive cycle?
I had a similar problem to yours only it had a sensor fault code for B1 s1.(forget the exact description) The customer had installed his own sensor (From E-Bay) and the scope displayed a pattern for an O2 sensor instead of an A/F sensor only the voltages were different. The connector was identical also. Replaced with the correct part..problem solved.
Nice diagnostics by the way.
Hey thanks wysetech2000! Yeah it was pretty interesting huh. I thought the crazy part was the fact he has driven it sense Aug. 1000's of mile and no codes and no drive cycle. Install correct AFR now it will run the monitor in 2 miles... just when you think you've seen it all.
It's always nice to find a problem that others couldn't find. It helps make it all worth while.
wysetech2000 Yeah we get a lot of the rejects at our shop. Mostly referrals from other shops. Always good for customer relations too. Usually builds a lifetime customer.
I didnt know my 2013 f150 5.0l used AFR on the upstreams.
Very thankful for this video, as with all your videos.
Educational Video , and your right an OBD II code reader will show almost a flat line display for the A/F sensors. Know you are swamped with questions but do you think hooking up a Tektronix oscilloscope will let me actually view the waveform. Thinking of pulling the trigger on a Snap-On scanner . Thank you.
I am not to sure how the dealership missed this. I know there are some bulletins out for this car, for Cats and ECM's with oxygen sensor and cat codes, but this is pretty cut and dry. Nice work.
+Hannah Belk no kidding! In my opinion there is no reason a make specific dealership should have missed this! Can't imagine how much the owner spent on parts going off uneducated guesses from other mechanics! ERIC'S THE MAN!!!
Want to let you know I appreciate your videos.
Very methodical approach. Do you think it was possible one of the previous people working on this vehicle put an a o2 sensor instead of a/f sensor.
***** Yep I believe that is what had happened...
You are a great teacher . i learn more from you than others. Thanks!!!!
Wow -- excellent work and amazing expertise! I wish I could find a mechanic as competent as you in my area!! Whatever your boss is paying you, he should double it -- seriously. Where else is a person going to find a mechanic as thorough, knowledgeable, and concerned about the customer? Mechanics of this caliber are EXTREMELY hard to come by -- I'm not joking.
Maybe you can do a video on how people can find a good repair shops in their area. There's just so much incompetence out there it's insane -- even at dealerships. Or should I say, ESPECIALLY at dealerships (in my experience). I don't particularly enjoy working on cars, but do as much of my own stuff as possible just because I've had many things damaged by gross negligence and incompetence. I've lost a lot of trust -- not that I'm going to get ripped off, just don't trust people will actually do a good job.
Well thank you! Thanks for watching too. I wasn't sure if any one would wanna watch a 30min video of me rambling about a AFR lol. And my boss paying me haha I wish lol. I own the shop so I don't even get a pay check. Customer satisfaction and not working for a boss (the man) is my pay. I don't really consider myself high caliber. As a matter of fact I am not ASE or ABC, or LMNOP or any other fancy acronym. I never went to collage, and as far as that goes I barley made it through high school. I grew up in my mom and dads shop and learned how to treat customers, run a business, work hard and do the best job you can. It is sad that we can't find mechanics who give a darn or want to do the best they can to help. It seems any more they just wanna play grab ass with there service writer, get the best pay flat rate jobs on the tickets and change parts then go home and drink beer... me, well I just have a desire to know how and why things work. Been that way sense I was a kid. Love seeing things work. As far as the dealership guys that is to bad. They have all that training at there finger tips and access to the best of everything for free, yet they just goof around and bounce job to job and don't really care. There pay scale drives them that way. They get paid on flat rate. It's all about turning hours, it really sucks for the customer though. No personal service, no talking to the tech. Just go go go or get fired. Any how I can ramble on that for ever. Thanks again for subscribing and watching!
Being cheap will sometime cost you more than taking a problem to the dealer - but we don't know how much other shops have charged or if they fixed problems not related to this error. Many have told me don't lift the hood until you have a problem which means little or no maintenance.
It's ok to get out of the comfort zone you did good very good of explaining o2 an AFR sensor I'll use this when I come across one thanks SMA
+Acrittendon Crittendon Thanks, I try my best :)
so this mystery is solved... new parts, correct or not can make others shoot off that parts cannon in a heart beat. toyota and lexus a/fr's will have a colored tape band around them, which toyota if ordered through them will be needed when replaced. unsure why, however a good quality correct denso part tends to do the job very well for most application from my experience. denso only has a failure rate of less than 1/2 of one percent, unless you are speaking of denso parts installed from the factory on a dodge. good find and good info
Great video. I think Pico has got some information about air fuel ratio sensors in database and some sample specimen traces? Good to upload traces of good and bad components for the information and learning database. Never ceases to amaze me they do this for free. I know their kit ain't cheap but so worth it for what buying in to.
The advantage of a V engine is you have two of each type of A/F sensors and oxygen sensors. This allows you to compare waveforms. With only one of each type like on an inline engine, it is possible to miss this problem.
Did the vehicle complete the drive cycle after this???
You've been a wealth of knowledge. Thanks for the videos
Eric, thanks for the help. I have a Toyota Sienna 2007 , though in my case, if I run at idle, AFS stays at 3.29 like in your case but when I accelerate and stop, it will drop all the way to zero and it will slowly ramp up to 3.29, only one time I saw it stay below 3 on one of them but it came back after the second throttle. I was watching the Long and short terms, when it is at idle, I see 7.XX & 10.XX (Long FT), when I accelerate and keep it, it stays at around 3 for both of them, when I accelerate just a little bit and keep it, it stays 4 & 7; the change is instant. I was thinking of a vacuum or bad data from the MAF but when I accelerate and decelerate, I see the MAF responding very well. The reason I'm concerned about the AFS is because at some point I did have a code on it but I would reset it and it would not come back until several months later. I did notice that the exhaust gets a little hotter over time because I can hear the cooling down noise lol. Please let me know what you think in this case. I currently have no codes stored.
Great lesson Eric O, I have a much better understanding how an AFR works. Thanks much!
Great info and I'm sure much appreciated. BTW You are not a bad teacher.
Thank you Eric you really helped me to understand these sensors. You rock!
Great job troubleshooting...
Enjoyed the whole process, logical thinking. Thank you.
4 exhaust sensors on a 4-banger...never seen that before! Bank1 and Bank2 were confusing at first; had to look up the layout on AllData to satisfy the curiosity haha
I know crazy right? I think it's like 1 and 4 on one and 2 and 3 on two or vice-verse...
I was reading the comments to see if someone commented about four sensors because I was confused as well. That's Toyota Japtronic technology for ya.
I know this is old but how does Toyota explain the nomenclature convention? Bank 2??
I guess they designed the fuel metering algorithm to be modular and adaptable their multi bank systems.
Where was the other primary sensor?
At 14:03 both values are about the same. The reason the left one looks to be bouncing is because the y-axis scale goes from 3.03 to 3.47, whereas the right one has a y-axis scale that goes from 2.00 to 4.15. Noticed the changed y-axis setting at 19:30, after the installation of the new O2 sensor. Why was this done?
What would sensor 2 look like on the sin wave and voltage? Would it graph like sensor 1 or would it jump around more?
I really enjoyed that! Thanks for sharing. Currently chasing down an AFR sensor on my 4Runner.
love the depth and the diagnosing procedures! but why tf did the dealsership not think to try that ?
Excellent diagnosis friend. I can see why the readings of the o2 sensor used as the AF sensor, would be all over the place, because of the way in which the two of them work are completely opposite. An A/F sensor, or Wide Band sensor, has more range, more precise readings. Although where they differ more so, is that an A/F sensor, unlike the o2 sensor, puts out a higher voltage reading as it becomes Rich, and lower voltage when reading Lean mixtures. (just the opposite of an O2 sensor.)
So, I am more than curious if in fact, your diagnosis, and repair corrected the vehicle's ability to "run a drive cycle" Did it? Thank You.
Sorry Eric, you’re wrong: you are an excellent teacher. I think you should leave this evaluation to your viewers. And we say you’re great.
Awesome video...
Great conclusion at the end . Also very informative regarding test and measurements with lean and rich testing sensors in data pids 👍
I liked to learn about problems and you explained in perfectly nice video..
I learn more from this guy at a much faster rate.
Hi Eric,Great video very informative ,great detail .even a dyi will be able to follow along
Thanks jimthecarguy I appreciate that. I will post a follow up video today. I just drove it this morning.
Ha I was just letting RUclips play videos for me and this came across. I fixed an 02 Avalon for this same problem yesterday. Only complaint was an abnormal shift.
That's my car! Got a 2002 RAV4 w/ 320K miles.
Put on a pair of gloves, yeah right Eric! I take it that it ran a complete drive cycle?