FINALLY! SOMEONE WHO ACTUALLY GETS HOW TO SHOW A ROOKIE LIKE MYSELF HOW TO CHECK FOR A FAULTY PART. THANK YOU BUDDY, EARNED ANOTHER SUB. KEEP UP THE GOOD WORK AND SHOW GUYS LIKE ME AND ALSO WALKING US THRU WHAT YOUR DOING, INSTEAD OF ASSUMING WE KNOW WHAT YOUR DOING. CLEAR AND STRAIGHT FORWARD VISUAL AND SPEAKING. YOUR AWESOME DUDE 👍🏾
just a note, the second oxygen sensor is not the one controlling the mixture for the ECU, its function is only to see that the signal when compared to the front sensor ist flat meaning the cat is functioning. The front sensor is used to test for air/fuel ratio and tell the ECU what mixture adjustment is required. So your faultcode could only come from the upstream (front) sensor. Downstream would cause a „Cat inefficient“ code on the motor warning. have fun, Bernhard
@@Xantylon74 I don’t know of any. It does not make a lot if sense since if the catalytic converter works fine all it gets is water and CO2 and there is no information about how the mixture was when it left the engine. A Lambda sensor is reading oxygen content to identify the current mixture which is only available prior to being converted by the Cat.
@@carlward9367 Hi Carl, since I don’t know exactly what your car does it is not good for me to tell you to change parts. I had it on my Jag that just the O2 heater relay was dead which is a lot cheaper than an O2 sensor. Can you get a readout of your sensors? Any activity there? The correct thing would be that the front sensor shows a sinewave like activity and if the cat works the downstream should display almost a straight line (konstant voltage). If both sensors show the same sinewave like activity then the Cat is bad. If there is no activity shown on the upstream sensor check powersupply else it is bad.
An oxygen sensor is made of zirconium oxide (ZrO2), a chemical compound used to form the sensor’s thermal-driven electrochemical fuel cell. Energy is generated by the difference of oxygen inside compared to the outside. Two platinum (Pt) electrodes are placed on the ZrO2 to provide a connection for output voltage to a control module. An output voltage of 0.2 V (200 mV) DC represents a lean mixture where there is a lot of oxygen in the exhaust stream. A reading of 0.8 V (800 mV) DC represents a rich mixture where there is little or no oxygen in the exhaust stream. The ideal point is 0.45 V (450 mV) DC - this is where the quantities of air and fuel are in the optimum - or stoichiometric - ratio
Auto Motive Diagnostic podcast covers narrow band O2 sensors really well. They don't actually measure oxygen, they use it as a catalyst to measure the hydrocarbons in the exhaust. There are also narrow and wide band sensors. Which ones are these?
Dude! There is a good reason you have almost a million views. Someone...you, finally showed (as Paul Harvey would say) the rest of the story on testing the O2 sensor. Thanks for that.
Man I absolutely miss my 97 Cherokee County! It had the strongest 6-cylinder engine I have ever driven! Torque for days! I'll have to say that was the most reliable vehicle I ever owned! Bought it used and paid $7000 for it in 2000 and drove it till 2017 and she never left me stranded! I'd trade my 2011 Sierra Texas Edition for your blue Cherokee!
This is an excellent demonstration of how to properly test the sensors works on almost every vehicle. I needed it because I am having troubles with my Toyota Camry and all indications from the OBDII lead me to the downstream sensor which is an unpleasant thing to reach. Looks like I can now at least test it before dealing with an unpleasantly hot exhaust system that needs to be dropped in order to remove said sensor. Thank you for a nice and concise video.
Oxygen sensors should be cleaned at 90K and 180K(replace them at 250K) by removing them and heating the sensing portion all around to cherry red with a propane torch, while checking response time with a volt meter. Using a meter while on the vehicle is not necessary as you can just hook up an OBD2 reader set to read live data. On an early fuel injected vehicle this method may be useful. *Edit for those not familiar with O2 sensors: there are four wires. Two are the same color, two are different colors. Connect your volt meter set to DC volts on the two wires which are different colors. Polarity doesn't matter.
@@merkey PO300 is random multiple misfire, usually related to the ignition system but not always. How many miles on your spark plugs? What is the impedance of your coils? As far as the low sensor voltage, look at your fuel trims. How does bank 2 compare with bank 1? Spray around the intake area with carb cleaner to check for vacuum leaks. Verify the fuel trim findings by looking at the spark plugs for signs of rich or lean condition.
@@alouiciousjackson5812 okay so i have brand new spark plugs and igition coils. short term fuel trim 11 0.0% and short term fuel trim 2 1 +25%. pulled plus definitely fuel but not like super black carbon rich still new
@@merkey short-term fuel trim bank 2 is plus 25%? Sounds like you have some bad injectors or a fuel pressure problem that it's trying to compensate for
A local Master mechanic has the best saying, it goes something like this: 'After spending all that money, saving all that money, fixing it yourself, then bring it to me and I'll fix it for you'. We've all had "easy fixes" which turn into changing all kinds of parts before we find out what the real issue is. What I do now is bring it to the mechanic shop, get it properly diagnosed and then evaluate whether I can do the job myself. I can save labor charges, if I can do it myself, without having to change all kind of parts and I can save time and headache from not having to diagnose it myself.
Great diagnosis Dale . You sure are teaching Sasha a lot and the cool thing in my book is that she shows a lot of interest . I have been trying to catch you live on Wednesday's but I have had a lot of doctors appointments on that day . I have about six more weeks of injections then I will be able to catch you all live again. Have a great weekend and be safe .
@@JeepSolid I have a P0420 code on my 2007 Toyota yaris but no engine light, I only found that out through Scan tool, what do I do because it is not smog ready, it given me the yellow exclamation mark rather than the green one. what do I do????could be I just have drive a few miles for it to go through the cycles, since it is only yellow and there no check Engine Light?
Thank you for your teaching video... very educational. I have a suggestion for you if I may. The old sensor that no good. Don't throw it away, You can use it as a tool. Cut the connector in half, hook up the old connector to the wire coming from the computer. With alligator clips on your meter, You can read the voltage better. The old oxygen sensor becomes a tool. Just a thought.
@@joeyperez3974 correct..... What you can do in that situation is buy or go to a you pull a part lot and cut one off. There's only a few variations of connectors so there is multiple vehicles that it will work to. You can also cut the nub off and and it will work on even more vehicles. Only difference usually tends to be the clocking of the pin and length of wire for most cars. Of course not all. For a more universal female plug you can cut the whole outer shield off just won't clip in.
My OBD2 Scanner said that I needed to replace the upstream oxygen sensor. I had already bought a new oxygen sensor prior to watching this lol so I was scared I bought it for nothing but I still have the receipts just in case I want to return it.. I did what you did in this video and turns out that I need a new oxygen sensor after all 😆
Why didn't you check the supply voltage to the heater? Both white wires, which should be ~12vdc. For the supply you checked the voltage on the grey and black wires on the supply side connector, which showed ~1.5Vdc. Those wires receive the voltage from the sensor, not send voltage to the sensor.
your obd scanner should display real-time voltage for each sensor on each bank, as well as fuel trims.... a multimeter externally used isn't really necessary then. But still useful if you have no scanner available.
Very well explained thanks. If the heater is disconnected then why should you expect the sensor to show voltage when running and with probes on the sensor wires. ?
Once enough warm exhaust gas passes over the sensor, it's got enough heat to start producing it's voltage. The heater is just there to get it up to operating temperature faster.
NTK is the ONLY brand you should buy for a Jeep YJ. I bought a denso and my nox has been high out of limits, it sputtered until warm after a month or two of using it. Went back to NGK/NTK 💥 got much better mileage, power & no more sputtering
The O2 sensor ahead of the catalytic converter works with PCM to regulate fuel mixture. The O2 sensor after the converter is used to determine the converter's efficiency (ie broken, failing, plugged up). You might be addressing that, but I'm only just starting to watch your vid.
@MrsBuddevil I'm no expert, and when it comes to the O2 sensors and catalytic converter, I'm a newbie. But, I'll try. With scan tool monitoring live data from O2 sensors. The O2 sensor ahead of the cat will cycle high and low as PCM adjusts fuel and air using sensor output. When car first starts, the O2 sensor behind cat will mimic the other sensor. When the cat's temp reaches operating temp, this output O2 sensor will give a steady signal which will fluctuate with engine speed. If everything is working, the cat is burning the waste gases, and if you measure the heat at the input and output of the cat, the output will be ~100 degrees hotter. If cat has failed, the output O2 will be erratic or still mimicking the input O2. The PCM will set error code, and you will fail emissions. If output O2 has failed, the PCM can't determine cat status, so it will set error code and you will fail emissions. Hope this helps.
At that point he was checking the wiring harness (not the sensor), so in simple terms , he was seeing how much voltage is coming through the wire that would be sent to the sensor . But instead was sent to his meter.
Great video! Thank you. Finally get it. Did your daughter learn how to do this? haha. Probably not interested. She's lucky to have a dad who can work on her over 20 year old car and drive a great Jeep. No longer make them like they used to. Loved the video. Thank you so much.
Thank you very much for identifying the sensor heating and O2 sensor wires involved on a 4 wire sensor. ...but mostly the voltages that are measurable that they are absent, or hopefully changing via sensation of O2. If I replace an O2 sensor again I will cut off the sensor to re-cycle the connector and wires to connect to the stripped wires rather than probing into the connectors for the next time I troubleshoot if the ECU is sending the heater voltage to the sensor.
@@MrsBuddevil no, they vary a lot, depending on manufacturer and position as well. Front and rear sensor plugs can be the same in appearance but have different little lugs that prevent them from being interchangeable. The shroud on the after cat sensor has much smaller holes ( like pin holes ) to restrict flow around the sensor. The before cat o2 sensor shroud has holes like, vents, would be the easy way to describe it, say, the size of the smallest type of grains for example, allowing the sensor greater exposure to the exhaust gasses because this one controls the fuel mixture ratio.
Isn’t it better to back probe for checking voltage so you don’t damage the pins inside? I was told by my teacher to never check from front and should always back probe
My 2000 XJ 4.0 130k miles was running like a champ but had a small crack in the original Duel Cat system throwing a permanent check engine light for Cat codes. No smoke, no black soot and was running like a champ. Stupidly I took it to an exhaust shop for a new replacement, close to factory Cat. Ever since they did the job the Jeep runs really rough, sounds like it's misfiring, black soot out of the tail pipe and sometimes the check engine light starts flashing? Not even comfortable driving this until I fix these new issues. Original dual cat system was unique to 2000-2001 XJ's I think..... there were 4 o2 censors in the original system, 2 upstream and 2 downstream, or something like that. The exhaust guy bypassed the front 2 o2 sensors, I think he patched up the bungholes or something and put in 2 new back o2 sensors. This is a custom exhaust shop that is well know in the area, people send their vehicles from out of state for work. Is it possible this guy is good at charging people lots of money to make their cars and trucks sound obnoxiously loud but knows nothing about my Jeep's Exhaust and totally F'ed it all up? Any advice on what to do now? How to bring my jeep back to stock-ish exhaust with no misfires and no black soot? Like I said, engine was perfect before this exhaust guy messed with the Cat and o2 sensors! He also messed up other parts of my exhaust system while working on the jeep and everything rattles like crazy. Any advice on good after market bold on close to custom exhaust in case I decide to just replace the whole system? This is a rust free/leak free/low miles garage queen and a future resto project so I wouldn't mind having a completely new system. I hear lots of people use Walker parts, any thoughts anyone? I'm doing a stock resto, as little modification as possible.
Take it back to the exhaust place and tell them to sort it out. Approach them in a friendly manner letting them know that you think they accidentally forgot to hook up the sensors again and now the vehicle is running rough, giving them a chance to fix fix their "oversight". If they don't play ball, you could get threaten to get the authorities involved (Environmental Protection Agency (EPA) if you don't have decent consumer protection laws, like most of USA) or just go straight to the authorities. It is illegal to remove or defeat an emissions control device on an automobile, and if they are a decent size operation that routinely does this, I'd expect the EPA to relish prosecuting them, as they did MagnaFlow.
Your jeep is what we call a California car. That means it's emissions control systems were made to comply with California law, which is stricter than most other states. The front 3 cylinders have their own cat and front and rear sensors, and the back 3 cylinders have their own cat and front and rear sensors. Without either front sensor connected, the computer will default to a stored program instead of paying attention to the exhaust content, and that program is only ideal for very specific conditions, and will run like dog crap in any other situation. If he left them connected but just tucked away somewhere, it's going to think the engine is lean and try to add fuel. Stored DTCs will sat which is the case. Idk the shop to say if there was malice, but they were definitely negligent. Any exhaust shop should have a basic knowledge of OBDII oxygen sensor strategy to know better than that. The only way to do what he did and get a good running vehicle would be to put a carburetor on it or an aftermarket engine management computer that doesn't require oxygen sensors.
Oscilloscope is a better device to check the O2 sensor voltage signal oscillating between 0.1 to 0.9 V, with a multimeter it is difficult to catch milliseconds voltage readings. Anyway thanks for your efforts.
I have been chasing a misfire on a 95 Pontiac OBD1.5 for over a month. First thing I tested was probe the o2. Getting volt at the ECM signal side (and heater) of the pigtail and 2-4 millivolts from O2 side. Plugged in, probing the wire, I get .4V +/- up to .9V spraying fuel into the TB. Every source I have found said there are no volts sent to O2 but .5+/- produced by the O2 so probe reading says it is good. Apparently the o2 is as good as the information I have gotten.
Lord! I wish I could bring my 2007 Commander to you! It needs love and the shops out here in Phoenix waiting to rip me off! I love the old girl and want her running straight! SMDH!
hi. I find this interesting. I have never used a digital meter. when testing o2 sencers. always. used analog. it makes it a lot easier. liked the videos. thank you.
Excellent young man. You and the sometimes annoying young man at Shrodinger are Awesome :)))) I tinker and barely know enough which gets me in trouble. I picked up a 2004 Durango 3.7 with 115 thousand original miles is a misfire pain in the butt. Had a compression test and leak down test which indicated very good. Changed original plugs and put new coil packs in. Ran for 30 miles and started misfiring. Once it started with cal 3 then 4, switching coil pack around would get it back running for another 25 or so miles. reader always has indicated low voltage bank 2 rear 02. Also reads IAT sensor has issues. My resistance between white o2 side wires is 4.4. You said it should be 5-7. It makes sense this could be an issue. Best; Tom
Nop...a faulty oxygen sensor cannot render a vehicle to misfire....quite often compression test misleads the diagnostics...go for cylinders leakdown test, it will precisely figure out issues of low compression (if any) due to ring-piston or intake/exhaust lifters or compromised head gasket. Erroneous reading in IAT renders quite rich fuel mixture, get it rectified first, then get your vehicle checked for air leak in intake manifold & associated hoses/pipes or air leak due to fsulty EVAP solenoid...EVAP solenoid is notoriou for air leaks and causing misfire kind of symptoms while you suddenly accelerate after you depressed the gas pedal. Moreover, get your PCV valve cleaned and pcv system both hoses checked for air leak or blockage in hose meant for pumping filtred air to head cover
How's the sensor producing voltage when it isn't plugged into the power system of the vehicle? Unless the voltage is coming into the sensor through a separate path, I'd guess that the resistance change (in Ohms) is what you should be measuring. I could definitely be wrong though as I'm unfamiliar with these sensors.
Hey my guy thank you so much it worked perfect for my problem is good to have this much detail when due you sellers are trying to fix their own problems 💯👍👍👍👍
The rear O2 sensor isn't commanding fuel trim changes though...it monitors the efficiency of the cat. Thus if you're having fuel trim problems, I don't see how it could be the rear O2, or why to check.
Which 02 sensor did you change. The upstream or downstream? Also which one should you change if you're getting poor gas mileage and a bit of jerking when accelerating at higher speeds (highway driving)
My 99 xj was throwing codes for O2 after cat. That sensor was telling the ECM that the motor was running lean (which it was not). In return since the ECM doesn't know any better, it was telling the injectors to add more fuel to compensate for the "lean" condition( which it did not need). This resulted into a severe rich condition. Rich means too much fuel. Too much fuel means serious drivability issues. Strong gas smell, terrible mileage, rough running and idling. Eventually bucking and slamming. Changed that O2 and it fixed the problem. No offense to jeepsolid but this is his rebuild. Mine was a daily car that I had to have because I'm poor. Change that O2 (only on jeeps).
Hello friend, is it ok to simply use the data stream feature on each O2 sensor using an OBDII reader? It seems like a little less trouble, or is this not an accurate diagnosis.
Yup, you are correct...when you see the jumping voltage values in obd data, it means sensor is doing its duty....BUT What if it doesn't show any voltage? Or obd gives you error code for this sensor, will you straight away change the sensor??? No, you need to varify
The difference in the amount of oxygen between that present in the outside air, and that present in the exhaust promotes the flow of oxygen ions and produces voltage.
I think I would like to pull the trouble code and throw new parts as hard as I can on my old cars to keep them running good and fix any issues loose or looking like it needs fixing or replacing because I drive older cars just to save money
O2 sensors generate voltage based on a difference in oxygen content between the exhaust gas and normal outside air. The bigger the difference, the higher the voltage.
P0071 - I had the same code on my kids car. 2013 Lancer. Ended up being a vacuum leak, but when you scan it and get that code it brings up a freaking list of things it could be like 10 different things to have to check. I easiest thing for me was to test for a leak first using the live data and then using a less tech method of just spraying carb and choke cleaner in the engine bay over the lines and when I hit the intake (air) hose BOOM, the idle leveled right out for about 8 seconds and then started acting up again. So in my case it was just a bad intake air hose.
Don't 02 sensors Voltage reading go from .00v (to lean) to 1.00v (to rich), .45 being ideal for stoichiometric efficiency? He said he just warmed up the engine. Looking for a tech. friend.
I can tell you must be a great Dad and fixing all your kids cars. LOL. Also, I think your title may limit your audience. Maybe 4WheelSolid, AutoSolid, MechSolid, etc........ Just a quick thought that came to mind.
When the sensor is disconnected, you mentioned voltage. Wouldn't that be resistance in ohms and not voltage since there is no power going to the sensor?
2005 Jeep Wrangler 4.0 all 4 sensors testing low on heater code P0031 - P0037-p0051-p0057 I replaced all with NGK and still lit on. I checked all the wires, disconnected the PCM, and continuity was all good, Pin 1-3-4 were good from the sensor to PCM plug and pin 2 to ground, my question is does pin 1 heater wire have 12v because I'm getting nothing as I understand on a cold start the PCM will circle a 12V + or 12V Negative signal to the heater. The circle will decrease to off as the sensor heats up. Thanks
Correct me if I’m wrong but the post cat oxygen sensor has nothing to do with the fuel injection, it’s sole purpose is to check that the cat is doing it’s job , the first position oxygen sensor is the reading that the ecu uses to adjust fuel injection
If the car was hot, or is running, the electrical charge is produced on the o2 sensor from a chemical reaction. As long as the sensor is warm/hot, you should get the reading he showed, regardless if its plugged into anything (on the wire side)
I have a 2007 dodge nitro 4X4 3.7, here's my question. If I replaced them with after market O2 sensors would my check engine still come on because their not the OEM from dodge. New O2 sensors I got has a didn't part #
My code reader says Htr.. emission code orange .. I think the sensor works but not the heater.. not cool I need a reader that is more specific.. no faulty code just a blinking Htr.. I just subscribed ☺️ thanks.. ken
![I.N "HALLUCINATION" | [Stray Kids : SKZ-PLAYER]](http://i.ytimg.com/vi/n5B5q1Hwt_U/mqdefault.jpg)
FINALLY! SOMEONE WHO ACTUALLY GETS HOW TO SHOW A ROOKIE LIKE MYSELF HOW TO CHECK FOR A FAULTY PART. THANK YOU BUDDY, EARNED ANOTHER SUB. KEEP UP THE GOOD WORK AND SHOW GUYS LIKE ME AND ALSO WALKING US THRU WHAT YOUR DOING, INSTEAD OF ASSUMING WE KNOW WHAT YOUR DOING. CLEAR AND STRAIGHT FORWARD VISUAL AND SPEAKING. YOUR AWESOME DUDE 👍🏾
just a note, the second oxygen sensor is not the one controlling the mixture for the ECU, its function is only to see that the signal when compared to the front sensor ist flat meaning the cat is functioning. The front sensor is used to test for air/fuel ratio and tell the ECU what mixture adjustment is required. So your faultcode could only come from the upstream (front) sensor. Downstream would cause a „Cat inefficient“ code on the motor warning.
have fun, Bernhard
AAh, very useful to know - gonna try cleaning my pre-cat sensor and see how that pans out!
He changed both so his readings were useless in this case. But aren’t there some newer cars using the downstream for the fueltrims too?
@@Xantylon74
I don’t know of any. It does not make a lot if sense since if the catalytic converter works fine all it gets is water and CO2 and there is no information about how the mixture was when it left the engine.
A Lambda sensor is reading oxygen content to identify the current mixture which is only available prior to being converted by the Cat.
@@bernhardlist9359 so should I just change my upstream O2 instead of both
@@carlward9367
Hi Carl, since I don’t know exactly what your car does it is not good for me to tell you to change parts. I had it on my Jag that just the O2 heater relay was dead which is a lot cheaper than an O2 sensor.
Can you get a readout of your sensors? Any activity there? The correct thing would be that the front sensor shows a sinewave like activity and if the cat works the downstream should display almost a straight line (konstant voltage). If both sensors show the same sinewave like activity then the Cat is bad. If there is no activity shown on the upstream sensor check powersupply else it is bad.
An oxygen sensor is made of zirconium oxide (ZrO2), a chemical compound used to form the sensor’s thermal-driven electrochemical fuel cell. Energy is generated by the difference of oxygen inside compared to the outside.
Two platinum (Pt) electrodes are placed on the ZrO2 to provide a connection for output voltage to a control module. An output voltage of 0.2 V (200 mV) DC represents a lean mixture where there is a lot of oxygen in the exhaust stream. A reading of 0.8 V (800 mV) DC represents a rich mixture where there is little or no oxygen in the exhaust stream. The ideal point is 0.45 V (450 mV) DC - this is where the quantities of air and fuel are in the optimum - or stoichiometric - ratio
My man breaking it down
Auto Motive Diagnostic podcast covers narrow band O2 sensors really well. They don't actually measure oxygen, they use it as a catalyst to measure the hydrocarbons in the exhaust. There are also narrow and wide band sensors. Which ones are these?
@@roadglide6895wide band
So 02 sensors produce electric?
Thankyou! I was wondering why that sensor was outputing voltage without anything connected to it.
Dude!
There is a good reason you have almost a million views. Someone...you, finally showed (as Paul Harvey would say) the rest of the story on testing the O2 sensor.
Thanks for that.
Man I absolutely miss my 97 Cherokee County! It had the strongest 6-cylinder engine I have ever driven! Torque for days! I'll have to say that was the most reliable vehicle I ever owned! Bought it used and paid $7000 for it in 2000 and drove it till 2017 and she never left me stranded! I'd trade my 2011 Sierra Texas Edition for your blue Cherokee!
This is an excellent demonstration of how to properly test the sensors works on almost every vehicle. I needed it because I am having troubles with my Toyota Camry and all indications from the OBDII lead me to the downstream sensor which is an unpleasant thing to reach. Looks like I can now at least test it before dealing with an unpleasantly hot exhaust system that needs to be dropped in order to remove said sensor. Thank you for a nice and concise video.
Oxygen sensors should be cleaned at 90K and 180K(replace them at 250K) by removing them and heating the sensing portion all around to cherry red with a propane torch, while checking response time with a volt meter. Using a meter while on the vehicle is not necessary as you can just hook up an OBD2 reader set to read live data. On an early fuel injected vehicle this method may be useful. *Edit for those not familiar with O2 sensors: there are four wires. Two are the same color, two are different colors. Connect your volt meter set to DC volts on the two wires which are different colors. Polarity doesn't matter.
I have bank 1 sensor 1 0.28v bank 1 sensor 2 0.28v bank 2 sensor 1 0.04 bank 2 sensor 2 0.30v. Po300 only 03 nissan 350z . Engine cold
@@merkey PO300 is random multiple misfire, usually related to the ignition system but not always. How many miles on your spark plugs? What is the impedance of your coils? As far as the low sensor voltage, look at your fuel trims. How does bank 2 compare with bank 1? Spray around the intake area with carb cleaner to check for vacuum leaks. Verify the fuel trim findings by looking at the spark plugs for signs of rich or lean condition.
@@alouiciousjackson5812 okay so i have brand new spark plugs and igition coils. short term fuel trim 11 0.0% and short term fuel trim 2 1 +25%. pulled plus definitely fuel but not like super black carbon rich still new
@@merkey short-term fuel trim bank 2 is plus 25%? Sounds like you have some bad injectors or a fuel pressure problem that it's trying to compensate for
@@merkey also check for vacuum leaks
I’ve seen people bench test them using a propane torch with out running the vehicle and it works great.
6pp
@@marymussa5118 huh ?
but you need to open the sensor first I supposed
WTF???
Yeah removing them is the hardest part here in NYS rust belt at least
A local Master mechanic has the best saying, it goes something like this: 'After spending all that money, saving all that money, fixing it yourself, then bring it to me and I'll fix it for you'. We've all had "easy fixes" which turn into changing all kinds of parts before we find out what the real issue is. What I do now is bring it to the mechanic shop, get it properly diagnosed and then evaluate whether I can do the job myself. I can save labor charges, if I can do it myself, without having to change all kind of parts and I can save time and headache from not having to diagnose it myself.
Great diagnosis Dale . You sure are teaching Sasha a lot and the cool thing in my book is that she shows a lot of interest . I have been trying to catch you live on Wednesday's but I have had a lot of doctors appointments on that day . I have about six more weeks of injections then I will be able to catch you all live again. Have a great weekend and be safe .
Thank you. You too!
l
2222
@@JeepSolid I have a P0420 code on my 2007 Toyota yaris but no engine light, I only found that out through Scan tool, what do I do because it is not smog ready, it given me the yellow exclamation mark rather than the green one. what do I do????could be I just have drive a few miles for it to go through the cycles, since it is only yellow and there no check Engine Light?
Thank you for your teaching video... very educational. I have a suggestion for you if I may. The old sensor that no good. Don't throw it away, You can use it as a tool. Cut the connector in half, hook up the old connector to the wire coming from the computer. With alligator clips on your meter, You can read the voltage better. The old oxygen sensor becomes a tool.
Just a thought.
genius
So it'll read the connector coming from the car only correct?? It won't read the cat. though huh?
@@joeyperez3974 correct..... What you can do in that situation is buy or go to a you pull a part lot and cut one off. There's only a few variations of connectors so there is multiple vehicles that it will work to. You can also cut the nub off and and it will work on even more vehicles. Only difference usually tends to be the clocking of the pin and length of wire for most cars. Of course not all. For a more universal female plug you can cut the whole outer shield off just won't clip in.
thats one really nice thing about a off road vehicle you dont need tp jack it up to work on most things
Thank you my friend for sharing your valuable technical advice with all those who need this important help, like yours. Many thanks.
Awesome! Even though I get a code on what O2 sensor to change, now I know how to use a meter to verify before swapping it out.
My OBD2 Scanner said that I needed to replace the upstream oxygen sensor. I had already bought a new oxygen sensor prior to watching this lol so I was scared I bought it for nothing but I still have the receipts just in case I want to return it..
I did what you did in this video and turns out that I need a new oxygen sensor after all 😆
Why didn't you check the supply voltage to the heater? Both white wires, which should be ~12vdc. For the supply you checked the voltage on the grey and black wires on the supply side connector, which showed ~1.5Vdc. Those wires receive the voltage from the sensor, not send voltage to the sensor.
Can you make a video to show us?
Now I can check my own O2 sensor and verify if it is faulty. Thanks for the information.
One of the most common codes... Great video. You are a damn good teacher.
your obd scanner should display real-time voltage for each sensor on each bank, as well as fuel trims.... a multimeter externally used isn't really necessary then. But still useful if you have no scanner available.
Great point
yes i use a obd reader and oxygen sensor 2 under cat says 0.45v nonstop and ecu says cat is not efficient
Not on an obd 1 system
Or if you have an older car like mine that is obd1 gotta love mitsubi
Great video, just to add it always better to back probe instead of possibly spreading the contacts inside the connector causing a bad or faulty result
High end test equipment is the same as I use! Great video..
i see what you did there :)
Very well explained thanks. If the heater is disconnected then why should you expect the sensor to show voltage when running and with probes on the sensor wires. ?
That’s just what I was looking for. To bad no one is responding.
Once enough warm exhaust gas passes over the sensor, it's got enough heat to start producing it's voltage. The heater is just there to get it up to operating temperature faster.
@@slowpoke96Z28 cheers mate. Good explanation 👍🇬🇧
NTK is the ONLY brand you should buy for a Jeep YJ. I bought a denso and my nox has been high out of limits, it sputtered until warm after a month or two of using it. Went back to NGK/NTK 💥 got much better mileage, power & no more sputtering
Thanks for taking the time to post this 👍
The O2 sensor ahead of the catalytic converter works with PCM to regulate fuel mixture. The O2 sensor after the converter is used to determine the converter's efficiency (ie broken, failing, plugged up). You might be addressing that, but I'm only just starting to watch your vid.
Is the second sensor absolutely necessary?
@MrsBuddevil I'm no expert, and when it comes to the O2 sensors and catalytic converter, I'm a newbie. But, I'll try. With scan tool monitoring live data from O2 sensors. The O2 sensor ahead of the cat will cycle high and low as PCM adjusts fuel and air using sensor output. When car first starts, the O2 sensor behind cat will mimic the other sensor. When the cat's temp reaches operating temp, this output O2 sensor will give a steady signal which will fluctuate with engine speed. If everything is working, the cat is burning the waste gases, and if you measure the heat at the input and output of the cat, the output will be ~100 degrees hotter. If cat has failed, the output O2 will be erratic or still mimicking the input O2. The PCM will set error code, and you will fail emissions. If output O2 has failed, the PCM can't determine cat status, so it will set error code and you will fail emissions. Hope this helps.
Thank you. Exactly what I was looking for.
I found this video to be informative and a good presentation.
Awesome channel very easy to understand technical directions just describe thumbs up baby love jeeps
Is that you Dale? It’s Nate. I used to work with you at Asante in Medford! This was a great video bro.
Oh shoot, hey Nate!
How long you been out?
@6:50 how are you getting any reading when it's unplugged?
At that point he was checking the wiring harness (not the sensor), so in simple terms , he was seeing how much voltage is coming through the wire that would be sent to the sensor . But instead was sent to his meter.
Great video! Thank you. Finally get it. Did your daughter learn how to do this? haha. Probably not interested. She's lucky to have a dad who can work on her over 20 year old car and drive a great Jeep. No longer make them like they used to. Loved the video. Thank you so much.
Thank you very much for identifying the sensor heating and O2 sensor wires involved on a 4 wire sensor.
...but mostly the voltages that are measurable that they are absent, or hopefully changing via sensation of O2.
If I replace an O2 sensor again I will cut off the sensor to re-cycle the connector and wires to connect to the stripped wires rather than probing into the connectors for the next time I troubleshoot if the ECU is sending the heater voltage to the sensor.
Are all o2 sensor connectors the same?
@@MrsBuddevil look up a bunch of different ones from auto zone etc. maybe you can see a difference from the pictures.
That's a good idea.
@@MrsBuddevil no, they vary a lot, depending on manufacturer and position as well. Front and rear sensor plugs can be the same in appearance but have different little lugs that prevent them from being interchangeable. The shroud on the after cat sensor has much smaller holes ( like pin holes ) to restrict flow around the sensor. The before cat o2 sensor shroud has holes like, vents, would be the easy way to describe it, say, the size of the smallest type of grains for example, allowing the sensor greater exposure to the exhaust gasses because this one controls the fuel mixture ratio.
Isn’t it better to back probe for checking voltage so you don’t damage the pins inside? I was told by my teacher to never check from front and should always back probe
multi meter probes can widen the holes on the sockets pins, and make poor connection.
Simple, clear, and to the point. Thank you.
Thanks your video is a great help, I need to check my sensors as I'm getting only half the milage that I was previously getting
Having the same issue, did you replace the O2 sensor and did it solve your poor gas mileage, thanks
My 2000 XJ 4.0 130k miles was running like a champ but had a small crack in the original Duel Cat system throwing a permanent check engine light for Cat codes. No smoke, no black soot and was running like a champ. Stupidly I took it to an exhaust shop for a new replacement, close to factory Cat. Ever since they did the job the Jeep runs really rough, sounds like it's misfiring, black soot out of the tail pipe and sometimes the check engine light starts flashing? Not even comfortable driving this until I fix these new issues. Original dual cat system was unique to 2000-2001 XJ's I think..... there were 4 o2 censors in the original system, 2 upstream and 2 downstream, or something like that. The exhaust guy bypassed the front 2 o2 sensors, I think he patched up the bungholes or something and put in 2 new back o2 sensors. This is a custom exhaust shop that is well know in the area, people send their vehicles from out of state for work. Is it possible this guy is good at charging people lots of money to make their cars and trucks sound obnoxiously loud but knows nothing about my Jeep's Exhaust and totally F'ed it all up? Any advice on what to do now? How to bring my jeep back to stock-ish exhaust with no misfires and no black soot? Like I said, engine was perfect before this exhaust guy messed with the Cat and o2 sensors! He also messed up other parts of my exhaust system while working on the jeep and everything rattles like crazy. Any advice on good after market bold on close to custom exhaust in case I decide to just replace the whole system? This is a rust free/leak free/low miles garage queen and a future resto project so I wouldn't mind having a completely new system. I hear lots of people use Walker parts, any thoughts anyone? I'm doing a stock resto, as little modification as possible.
Take it back to the exhaust place and tell them to sort it out. Approach them in a friendly manner letting them know that you think they accidentally forgot to hook up the sensors again and now the vehicle is running rough, giving them a chance to fix fix their "oversight". If they don't play ball, you could get threaten to get the authorities involved (Environmental Protection Agency (EPA) if you don't have decent consumer protection laws, like most of USA) or just go straight to the authorities. It is illegal to remove or defeat an emissions control device on an automobile, and if they are a decent size operation that routinely does this, I'd expect the EPA to relish prosecuting them, as they did MagnaFlow.
Your jeep is what we call a California car. That means it's emissions control systems were made to comply with California law, which is stricter than most other states. The front 3 cylinders have their own cat and front and rear sensors, and the back 3 cylinders have their own cat and front and rear sensors. Without either front sensor connected, the computer will default to a stored program instead of paying attention to the exhaust content, and that program is only ideal for very specific conditions, and will run like dog crap in any other situation. If he left them connected but just tucked away somewhere, it's going to think the engine is lean and try to add fuel. Stored DTCs will sat which is the case.
Idk the shop to say if there was malice, but they were definitely negligent. Any exhaust shop should have a basic knowledge of OBDII oxygen sensor strategy to know better than that. The only way to do what he did and get a good running vehicle would be to put a carburetor on it or an aftermarket engine management computer that doesn't require oxygen sensors.
Oscilloscope is a better device to check the O2 sensor voltage signal oscillating between 0.1 to 0.9 V, with a multimeter it is difficult to catch milliseconds voltage readings.
Anyway thanks for your efforts.
Grest instructions. Easy to see what you are doing. Appreciate your time!!!
This is quite informative, thanks for sharing your knowledge wise one.
Thank you very much! This is a very nice instructional video! You did It in a very simple and easy way to understand! Keep them coming……….
I have been chasing a misfire on a 95 Pontiac OBD1.5 for over a month. First thing I tested was probe the o2. Getting volt at the ECM signal side (and heater) of the pigtail and 2-4 millivolts from O2 side. Plugged in, probing the wire, I get .4V +/- up to .9V spraying fuel into the TB. Every source I have found said there are no volts sent to O2 but .5+/- produced by the O2 so probe reading says it is good. Apparently the o2 is as good as the information I have gotten.
You're the only one who explained to me the problem of the lambda sensor.
Thank you!
Sorry for just asking: At 5:38. The sensor is disconected from the car and produces a voltage just by sitting in the pipe?
Yes, it does but when it's get hot upto 400 charli approx
Thank you for your advice. Have a great weekend
Those Cherokee's were really good vehicles in those years.
Lord! I wish I could bring my 2007 Commander to you! It needs love and the shops out here in Phoenix waiting to rip me off! I love the old girl and want her running straight! SMDH!
Quite thorough! Apperceptive! I subscribed!
Great information but what were the symptoms when driving? Thanks and God Bless.
Thanks this was most informative and easy to follow visually. I’m going to try it now
How do you know what the readings for each test should be?
Man I miss my Jeep. That bad boy undercoated? That frame looked beautiful
Excellent way to describe the process and why it's not working.
hi. I find this interesting. I have never used a digital meter. when testing o2 sencers. always. used analog. it makes it a lot easier. liked the videos. thank you.
Great content. Have the blessed day!
at 1:45. would you only be getting the excess fuel injected momentarily, like till the ECU or PCM adjusts to the new part
Excellent young man. You and the sometimes annoying young man at Shrodinger are Awesome :))))
I tinker and barely know enough which gets me in trouble.
I picked up a 2004 Durango 3.7 with 115 thousand original miles is a misfire pain in the butt.
Had a compression test and leak down test which indicated very good.
Changed original plugs and put new coil packs in.
Ran for 30 miles and started misfiring. Once it started with cal 3 then 4, switching coil pack around would get it back running for another 25 or so miles.
reader always has indicated low voltage bank 2 rear 02.
Also reads IAT sensor has issues.
My resistance between white o2 side wires is 4.4. You said it should be 5-7.
It makes sense this could be an issue.
Best; Tom
Nop...a faulty oxygen sensor cannot render a vehicle to misfire....quite often compression test misleads the diagnostics...go for cylinders leakdown test, it will precisely figure out issues of low compression (if any) due to ring-piston or intake/exhaust lifters or compromised head gasket.
Erroneous reading in IAT renders quite rich fuel mixture, get it rectified first, then get your vehicle checked for air leak in intake manifold & associated hoses/pipes or air leak due to fsulty EVAP solenoid...EVAP solenoid is notoriou for air leaks and causing misfire kind of symptoms while you suddenly accelerate after you depressed the gas pedal.
Moreover, get your PCV valve cleaned and pcv system both hoses checked for air leak or blockage in hose meant for pumping filtred air to head cover
Greetings from Venezuela! good good channel about jeep especially about 242 engines
Thank you!
THANK YOU BROTHER. GREAT EXPLANATION
Thanks for making this video. Still need to find some time to replace the sensors on my XJ. No codes, no hurry 😄
Yep. Ain't broke don't fix. Lol 🤣
How's the sensor producing voltage when it isn't plugged into the power system of the vehicle? Unless the voltage is coming into the sensor through a separate path, I'd guess that the resistance change (in Ohms) is what you should be measuring. I could definitely be wrong though as I'm unfamiliar with these sensors.
You are Correct, 02 sensors Do Not produce Voltage.
Unlesss its an 02 sensor/dynamo. Lol. 😜
They produce voltage when heated, Google is your friend
@@ovwok You are Right, i just google and read about that, thanks for teaching me something new today.
датчик из циркония, он при контакте с О2 вырабатывает напряжение...
It's chemistry. When there's a difference in oxygen content on either side of the actual sensing element, it generates a small voltage.
Hey my guy thank you so much it worked perfect for my problem is good to have this much detail when due you sellers are trying to fix their own problems 💯👍👍👍👍
The rear O2 sensor isn't commanding fuel trim changes though...it monitors the efficiency of the cat. Thus if you're having fuel trim problems, I don't see how it could be the rear O2, or why to check.
I like your work you are good electronic man
cool video❤ I learned a lot of things 😃 thank you for the upload i appreciate it👌🏻
Good step by step demo.
Which 02 sensor did you change. The upstream or downstream? Also which one should you change if you're getting poor gas mileage and a bit of jerking when accelerating at higher speeds (highway driving)
He replaced downstream after the converter check for engine codes it will tell u what one to check
What you were reading was a variation in resistance in ohms
My 99 xj was throwing codes for O2 after cat. That sensor was telling the ECM that the motor was running lean (which it was not). In return since the ECM doesn't know any better, it was telling the injectors to add more fuel to compensate for the "lean" condition( which it did not need). This resulted into a severe rich condition. Rich means too much fuel. Too much fuel means serious drivability issues. Strong gas smell, terrible mileage, rough running and idling. Eventually bucking and slamming. Changed that O2 and it fixed the problem. No offense to jeepsolid but this is his rebuild. Mine was a daily car that I had to have because I'm poor. Change that O2 (only on jeeps).
Our 99 wrangler has the same issue, did you change the upstream or downstream sensor?
fantastic explanation, what made you decide to replace both? can I get away with doing just the one with a bad/no signal? thanks again
Cool, I will do the same on my Civic Coupe 97 with 280,000 miles.
That may be a wideband sensor. If so, these methods won't work exactly the same.
Hello friend, is it ok to simply use the data stream feature on each O2 sensor using an OBDII reader? It seems like a little less trouble, or is this not an accurate diagnosis.
Yup, you are correct...when you see the jumping voltage values in obd data, it means sensor is doing its duty....BUT What if it doesn't show any voltage? Or obd gives you error code for this sensor, will you straight away change the sensor??? No, you need to varify
How does the o2 sensors have power to send the signal when it is disconnected running that last test?
The difference in the amount of oxygen between that present in the outside air, and that present in the exhaust promotes the flow of oxygen ions and produces voltage.
I think I would like to pull the trouble code and throw new parts as hard as I can on my old cars to keep them running good and fix any issues loose or looking like it needs fixing or replacing because I drive older cars just to save money
Thank you for the video. Was a great help. God bless.
Imagine having a genius mechanic for a dad who can fix any problem with your car.
Ian in full custom garage
Great video. One of the comments was about using the OB2 scanner. Did you try this also??
Thanks
Thanks for the video and learning is very essential
Thanks for the effort dude..great vid
How are you getting voltage out of a disconnected o2 sensor?
O2 sensors generate voltage based on a difference in oxygen content between the exhaust gas and normal outside air. The bigger the difference, the higher the voltage.
It's an electro-chemical reaction, like in a battery.
@@slowpoke96Z28 thx
Thanks mate, super clear explanation.
P0071 - I had the same code on my kids car. 2013 Lancer. Ended up being a vacuum leak, but when you scan it and get that code it brings up a freaking list of things it could be like 10 different things to have to check. I easiest thing for me was to test for a leak first using the live data and then using a less tech method of just spraying carb and choke cleaner in the engine bay over the lines and when I hit the intake (air) hose BOOM, the idle leveled right out for about 8 seconds and then started acting up again. So in my case it was just a bad intake air hose.
Don't 02 sensors Voltage reading go from .00v (to lean) to 1.00v (to rich), .45 being ideal for stoichiometric efficiency? He said he just warmed up the engine. Looking for a tech. friend.
if mine shows only 0.45 and error cat is not efficient
On this model year jeep, yes.
Great test procedure. Thank You.
This was useful. Thank you. Going to check out what other gold nuggets you have on your videos.
I can tell you must be a great Dad and fixing all your kids cars. LOL. Also, I think your title may limit your audience. Maybe 4WheelSolid, AutoSolid, MechSolid, etc........ Just a quick thought that came to mind.
Great job on the video. We have similar style!!
Excellent explanation. Thank you!
Great video and info .Excellent
When the sensor is disconnected, you mentioned voltage. Wouldn't that be resistance in ohms and not voltage since there is no power going to the sensor?
No o2 sensors create a small voltage when hot and have oxygen present.
2005 Jeep Wrangler 4.0 all 4 sensors testing low on heater code P0031 - P0037-p0051-p0057 I replaced all with NGK and still lit on. I checked all the wires, disconnected the PCM, and continuity was all good, Pin 1-3-4 were good from the sensor to PCM plug and pin 2 to ground, my question is does pin 1 heater wire have 12v because I'm getting nothing as I understand on a cold start the PCM will circle a 12V + or 12V Negative signal to the heater. The circle will decrease to off as the sensor heats up.
Thanks
Correct me if I’m wrong but the post cat oxygen sensor has nothing to do with the fuel injection, it’s sole purpose is to check that the cat is doing it’s job , the first position oxygen sensor is the reading that the ecu uses to adjust fuel injection
@3:10 those two white wires looked chewed on. If the wire is exposed and dirty greasy/oil coated them, it could be shorting them...
Never use multimeter with active "low battery" indicator. This cause a higher measured level than the real one.
So how would check?
@@dannymartinez8522 With multimeter with charged battery inside.
at 4:05, why do you check if the sensor is getting power/voltage? isn't the sensor the one to generate the voltage?
If you have a scan tool that shows live data, you can see this also, without going under the vehicle.
How did you get a voltage reading from the 2 grey/white wires on the rear 02 sensor without the negative and positive (power) connected to the jeep?
If the car was hot, or is running, the electrical charge is produced on the o2 sensor from a chemical reaction. As long as the sensor is warm/hot, you should get the reading he showed, regardless if its plugged into anything (on the wire side)
I have a 2007 dodge nitro 4X4 3.7, here's my question. If I replaced them with after market O2 sensors would my check engine still come on because their not the OEM from dodge. New O2 sensors I got has a didn't part #
Great video, I need to check mine now that I know how. 👍🏼🇦🇺
A superb video sir.
My code reader says Htr.. emission code orange .. I think the sensor works but not the heater.. not cool I need a reader that is more specific.. no faulty code just a blinking Htr.. I just subscribed ☺️ thanks.. ken