This is the best VIDEO explaining O2 sensors behavior . So many videos on this subject on YT, however all have spaghetti shaped information, unclear and disorganized or vague . This one nailed it. Thumbs up man. You should be teaching classes.
Thanks for the info man, diagnosing mine for sudden loss of power after a while of driving. Mine is the inline 6 engine, so only 1 o2 before and 1 o2 after. I thought it couldve been the cat, but the charts look like your top 2 o2 readings. They look perfect. Thanks for this info again
Such a nice and simple explanation, and finally, someone mentions that the graphs should look different between sensor 1(up and down constantly) and 2 (a steady reading).
You can further verify cat performance but checking the temp of the exhaust pipe before and after the cat. Exhaust temp after the cat should be much cooler on a properly working cat. If the temp didn't change much, the cat definitely isn't doing it's job. That's a second test for confirmation.
Love this video Straight to the point . Unlike others video that want to tell use all about their life story than 2min of the video u get nothing. Keep it up thanks
Love the video dude! Explaining the difference of a narrow band that you're working on here I believe is important information to note you're NOT talking wideband! Im definitely a shade tree mech here so I'm no mechanic in that sense of schooling but im learning lambda a/f sensors! They definitely read differently! Great video for a narrow band buddy! Not talking shit bro just it's good to share that info I think
First question, In your video, was the vehicle engine idling or did you have it up at some specific RPM? I notice my post-cat sensor readings look flat during idle but sometimes in the .3mV range, sometimes in the .7 or .8 mV range. But when highway driving (~2200 RPM), it's switching up and down making me think the cat is bad. Is that normal for the O2 readings to behave differently in those two regimes? Second question, how can you test if the O2 sensor itself is working fine and not fooling you into thinking the cat isn't working correctly? I know the O2 sensor is pretty cheap compared with the cats, so guess I can go ahead and swap them out and see if problem remains, but is there a specific test you can perform on the O2 sensor to know if it's the problem instead of the cat? Thanks!
I am trying to figure out if my B1S1 is bad or if cat is having issues or if something else is wrong. How do I know if the sensor itself is bad? It wouldn't go up and down as much or at all? When my car was idle, my muffler was rattling from the inside and got a P0420 code for low cat efficiency. Mentionned it to my mechanic and he had a look he said baffle seems broken so he replaced my muffler but he was not sure yet why the code and it seemed unlikely that it was caused by the muffler. After muffler replaced, the code eventually came back ( it has been coming and going). And when i rev low (kind of using the torque of the car to speed up) the exhaust gets really loud, kind of sounding like those cheap honda civic diy race cars. Its not super consistent but fairly easy to reproduce. I am going to do more troubleshooting afterwork, but if you have any ideas, let me know. Thanks!
In this example did the Bank 2 O2 sensor throw a DTC. Chasing a P0300 on my 07 escalade and I'm thinking of replacing the O2 sensors but I have no O2 codes pending or current.
What I don't understand is, when the Toyota corolla 4afe manual says that you must measure 8 or more fluctuations in 10 seconds . Does this means that you must count how many times it goes to 1volt as 1 fluctuation, or should you count the up and downs as 2 fluctuations? I mean, does an up and down circle, means 1 fluctuation or two?
I have a 0420,0430 codes on my 2014 Infiniti QX80 and I was using my Autel Maxicom 808 trying to diagnos if I need a catalytic or 0/2 sensors my air fuel volts were the same on each O/2 sensors bank 1 /2 was 1.2 and Bank 2 /2 was the same.And Bank 1/1 and 1/2 was the same .28 what can I look at next to find the right readings if those are not it
I have a 02chevy 5.3 I have fixed the exhaust manifold leaks and change all of the o2 sensors and catalytic converter on bank 1 because I keep getting p420 code. Not sure exactly what to do next
Your GOOD sensor 2 example and BAD sensor 2 example is the complete opposite as to what I have going on. Possible someone swapped plug connections on my car. They plug into the same area on car.
Great Video! My bank 2 sensor doesn't move from 1.25V. Have a p0158 code 02 circuit high voltage. I'm leaning towards a clogged catalytic converter even though I don't have a p0420 code. I may have a bad ground with a reading of 23 ohms on the ground wire.
Great video and we’ll explained I have a psa citreon c4 1.2 eb pure tech reading downstream oxygen sensor reading too high watching that video tells me it’s the catylitic converter
how would the 1st O2 sensor readings be like when there is a vacuum leak near the intake manifold and while idle? should they stuck around 0.02v or oscillate around low values ? (Thanks for the video!)
I have a Ford expedition 2002, V8 5.4L I replaced a pipe under the intake manifold, a heater hose connected to the water pump, change new intake, replace spark plugs, coil packs, O2 sensors Now I have 2 codes p1152 and p1132 took it to get it diagnosed. I need to replace both front oxygen sensor first and erase the code. Run car until code turn off if the code comes on again I’ll need to bring it to dealer and replace computer.
The Bad Cat signal period is different from the upstream. Shouldn't the downstream have the same period as the upstream? (How can the downstream hold steady for a while and then dip? What is the process?
My Forscan reading shows bank 1 sensor 1 reading in Current mA or Imped V. I don't have a reading in mV like your scan tool shows.I'm getting a P219A code, Lean bank 1, and the mA reading goes from 0.00 to -0.11, and the V reading is 1.02 to 1.01. Does this indicate a bad O2 sensor? Thanks!
2000 express 5.7. No check engine light. On a long pull hill o2 show good but engine stalls progressively worse as the van goes up the hill. New cats and air flow sensor. Like not getting gas. In use of scope what should I be looking at.
I have a issue with my 02 sensor 1 bank 1 in my Murano first replacement on it came out with a voltage of 2.4 to 2.8 so I got another one now this one is putting out 1.5 to 1.8 for what I can see I shouldn't be having any other issues but a bad sensor do you think I'm right both sensor I purchase from Amazon e and eBay we're around 60 dollars your knowledgeable opinion could crack this case pleas let me know Ifvyou think paying the 231 dollars at AutoZone will fix this issue
At 1:20 you say we should see switching multiple times per second. But the graph is switching much slower than that, about 2 seconds for a full up and down. Yet you say it looks like those sensors are normal. I have to say it sounds contradictory. Could you please clear that up for me?
2014 Hyundai Elantra 1.8L Consistent P0420 code While looking at Sensor 2 reading, while driving on the highway, the voltage does switch some down to 0.1 volts but at idle it stays at 0.7 - 0.75 volts Also, while driving at highway speeds, when I take my foot off the accelerator and let the vehicle coast, the voltage goes to 0.000 volts and stays there until I push the accelerator again. I'm unable to look at the upstream voltage. I'm using Blue Driver and it says the PID is unavailable I'd like to condemn the post cat O2 sensor but I don't think I have enough evidence.
2012 Jeep Wrangler- I had a fault for bank 2 sensor 2, so with 130k miles on the Jeep, I replaced all 4 sensors. I am still getting the same p0158 fault code as before, so I hooked up my scanner and the bank 2 sensor 2 is showing a steady 1.275 volts that never changes, regardless of engine rpm or fuel delivery while the others fluctuate as normal. I ran some Catacleaner through the Jeep as per the instructions on the bottle. I didn't expect a complete fix, but I wanted to see if it would at least open the cat up enough to show a change on the sensor data, which it did not accomplish. I'm pretty much stuck now and don't really have the money to replace the cat, especially if that's not the issue. Would a bad wire or corroded ground cause the voltage to stay at a constant voltage like this?
Please help me, i used an ODB reader. The upper o2 is ok jumps up and down like in the video. The downstream stays almost straight but 100, 115 to 120.
I have a NOx absorber B2 fail when i did a monitor test with a code reader but i can't seem to find out what a NOx absorber B2 is... i take it the B2 is bank 2 and the NOx is an oxygen sensor but where is this... upstream or downstream. i have a Ford Focus 2009 1.6 TDCI any help would be highly appreciated 🙏
On my scanner hooked up to a Honda Element, I get O2S B1S1 in mA and Lambda B1S1 in a unit-less value. How do I compare with readings like yours in mV?
Question, so my o2 sensor is just staying at 0.02v at idle, it can jump to a max of 4.9 when i rev it, so the data it's sending is faulty, but my question is, are there other factors that can make it rub such low voltage on idle, this is the pre-cat o2 sensor.
Question concerning a 2005 Honda Accord 3.0.....v6.....my bank 1 sensor 1 is barely reading 0.04 mili Amps.....and bank 2 sensor 1 is reading the same thing!! Is this the reason why my fuel trim is off? Computer tripped a p0171 code .....lean condition.
I have a 2000 tacoma v6. I recently had a p301 cyl 1 misfire and p0300 random misfire codes. Found a bad cyl 1 injector, replaced it and the code went away and check engine light disappeared. A few days later, I get a new check engine code for p0420 catalyst below threshold bank 1 (my scanner doesnt say which sensor just says bank 1). I get my obd2 scanner and check live data and at idle my upstream sensor reads from 0.00 to 900, fluctuating in between every second like you described and the downstream sensor is slowly fluctuating from 3.254 to 3.300. Not sure what to make of this but if I understand what you're explaining is that my B1S1 (upstream before cat) is working properly and the B1S2 (after cat) is not? Help would be greatly appreciated
I thought stoichiometric readings only came from downstream o2? I have a sienna with pre cats, and the readings fluctuate but stay roughly the same number
How can you tell from number data that a sensor is bad?... 2003 camry sensor 2 while driving drops to 0 especially while accelerating is that normal or no? Getting a p0420 code just trying to rule out everything before replacing a cat
Awesome video and straight to the point. My question is on bank one I’m getting s1 between .01 and .90 and s2 between .030 and .810 On bank 2 s1 is .065 and .885 and s2 between .065 and .715 I am at my wits end with trying to complete the catalyst monitor and I can’t smog the vehicle What do you believe the problem is, all your help is appreciated Thank you
That tells you that you have bad cats. Thus the reason you cant complete the cat monitor. If the cats are working you would see a steady voltage reading on both secondary sensors.
I have a Nissan FG10 model, engine QG15 (DE) can I swap 3 wire 02 sensor for 4 wire sensor. If adviceable, what are the connection as it is less 1 wire?
Have a 2003 explore 4.0 with bank 1 sensor 1 reading between 0.00 and 0.780. Similar with bank 2 sensor 1 and scan tool is reading lean condition on both with a rough idle. What’s your thought?
could i ask a quick question , my sensor 2 was pegged at constant 1.27v , dash light on , i guessed the sensor was broken and replaced it , now its flickering around 0.1 v or so , so not following your example of a dead cat , could it still be the cat?
Are there any scan tools that instead of showing you a bunch of graphs, numbers, and abbreviations, it tells you a more meaningful conclusion such as "O2 sensor bad, please replace"?
Hey, my pre-cat is fluctuating every 5 seconds mostly hanging in the 0.7-8V range. I’m also getting a P0171 running lean code. No visible vacuum leak after smoke test. What could it be?
Is it normal for sensors to put out readings while off, overnight. My 17 GMC sierra bank 2s1 reads +1 and b2s1 reads +12 while off... thank you in advance
Hello, my Fiat Bravo 1.6 multijet is showing between 10-12 g/s on idle. I think this is too much for this engine? Also, sometimes the car idle is not stable and the rpm are moving. When I observe the MAF in that situation it is moving on idle between 1.5 - 13 g/s. Will cleaning the MAF with a spray will help? Thanks in advance!
Hi what is a normal reading number for bank 1 and 2? My car getting .267 on bank 1 sensor 1 and .675. Flat And same number on bank 2 But still have p0429? Can you advice
![FNAF Into the Pit has A LOT of Unused Graphics | LOST BITS [TetraBitGaming]](http://i.ytimg.com/vi/6YhZCRdipl4/mqdefault.jpg)
As a forme ASE certified automotive technician, this is the best simple explanation I have seen in a very long time.
As the video randomly auto played on my phone, I agree
I agree!
Just watched this video in the cab of a truck I’m diagnosing 😂 you’re a saint man thanks for the clear cut straight to the point Info
This is the best VIDEO explaining O2 sensors behavior . So many videos on this subject on YT, however all have spaghetti shaped information, unclear and disorganized or vague . This one nailed it. Thumbs up man. You should be teaching classes.
no wasting time, straight to the point, love videos like this, thank you this was very helpful!!
Thanks for the info man, diagnosing mine for sudden loss of power after a while of driving. Mine is the inline 6 engine, so only 1 o2 before and 1 o2 after. I thought it couldve been the cat, but the charts look like your top 2 o2 readings. They look perfect. Thanks for this info again
Very well explained, I come back here often to refresh my knowledge on this
What a great great explanation it’s the first time I’ve actually seen a video that makes sense. Thank you so much.
Such a nice and simple explanation, and finally, someone mentions that the graphs should look different between sensor 1(up and down constantly) and 2 (a steady reading).
You can further verify cat performance but checking the temp of the exhaust pipe before and after the cat. Exhaust temp after the cat should be much cooler on a properly working cat. If the temp didn't change much, the cat definitely isn't doing it's job. That's a second test for confirmation.
Love this video Straight to the point . Unlike others video that want to tell use all about their life story than 2min of the video u get nothing. Keep it up thanks
Great info. It should fluctuate on the front sensor .01 to .09
But on the sensor after the cat
Should be flat . I am using spacer extentions
This was very helpful. Need to diagnose a P420 on a 07 Toyota Camry. I suspect the Oxygen sensor but need to verify that first.
Excellent video, I already knew most of this but it was a good refresher
Concise explanation even if I still can't wrap my heads around it. It at least points me in the right direction.
Love the video dude! Explaining the difference of a narrow band that you're working on here I believe is important information to note you're NOT talking wideband! Im definitely a shade tree mech here so I'm no mechanic in that sense of schooling but im learning lambda a/f sensors! They definitely read differently! Great video for a narrow band buddy! Not talking shit bro just it's good to share that info I think
First question, In your video, was the vehicle engine idling or did you have it up at some specific RPM? I notice my post-cat sensor readings look flat during idle but sometimes in the .3mV range, sometimes in the .7 or .8 mV range. But when highway driving (~2200 RPM), it's switching up and down making me think the cat is bad. Is that normal for the O2 readings to behave differently in those two regimes?
Second question, how can you test if the O2 sensor itself is working fine and not fooling you into thinking the cat isn't working correctly? I know the O2 sensor is pretty cheap compared with the cats, so guess I can go ahead and swap them out and see if problem remains, but is there a specific test you can perform on the O2 sensor to know if it's the problem instead of the cat? Thanks!
Same here. I would like to know exactly if he was at a certain rpm or idle.
Did you ever find out what the issue was?
Very good video, short and to the point. Thanks Hunter!!
Excellent video 👏👊
Good explanation. I use the O2 all the time .
How do you know if catalytic converter is bad or 02 sensor?
That was articulated very well. Well done.
Great video. Very well explained
I am trying to figure out if my B1S1 is bad or if cat is having issues or if something else is wrong. How do I know if the sensor itself is bad? It wouldn't go up and down as much or at all? When my car was idle, my muffler was rattling from the inside and got a P0420 code for low cat efficiency. Mentionned it to my mechanic and he had a look he said baffle seems broken so he replaced my muffler but he was not sure yet why the code and it seemed unlikely that it was caused by the muffler. After muffler replaced, the code eventually came back ( it has been coming and going). And when i rev low (kind of using the torque of the car to speed up) the exhaust gets really loud, kind of sounding like those cheap honda civic diy race cars. Its not super consistent but fairly easy to reproduce. I am going to do more troubleshooting afterwork, but if you have any ideas, let me know. Thanks!
How is the O2 sensor reading between idle vs while driving?
Top explanation my friend many thanks👍🏻👍🏻
Could you explain how to know if the o2 sensor is bad? Great video thanks!
Short and informative. Nice!
In this example did the Bank 2 O2 sensor throw a DTC. Chasing a P0300 on my 07 escalade and I'm thinking of replacing the O2 sensors but I have no O2 codes pending or current.
Scan tools don't identify faulty or bad components (parts). TEST don't guess. Best wishes!
How would you know if you had a bad rear o2 sensor not doing it’s job or if the cat is at fault not doing it’s job?
Good question. Hope somebody who knows the answer can reply.
Perform a propane test. Scanner danner discusses this in several videos and in his book 👍🏻
What I don't understand is, when the Toyota corolla 4afe manual says that you must measure 8 or more fluctuations in 10 seconds . Does this means that you must count how many times it goes to 1volt as 1 fluctuation, or should you count the up and downs as 2 fluctuations? I mean, does an up and down circle, means 1 fluctuation or two?
I have a 0420,0430 codes on my 2014 Infiniti QX80 and I was using my Autel Maxicom 808 trying to diagnos if I need a catalytic or 0/2 sensors my air fuel volts were the same on each O/2 sensors bank 1 /2 was 1.2 and Bank 2 /2 was the same.And Bank 1/1 and 1/2 was the same .28 what can I look at next to find the right readings if those are not it
Beautiful job, simple and easy 👌
I have a 02chevy 5.3 I have fixed the exhaust manifold leaks and change all of the o2 sensors and catalytic converter on bank 1 because I keep getting p420 code. Not sure exactly what to do next
Your GOOD sensor 2 example and BAD sensor 2 example is the complete opposite as to what I have going on. Possible someone swapped plug connections on my car. They plug into the same area on car.
Great video !!!
Thank you for sharing your experience!! Great video👍
Great Video! My bank 2 sensor doesn't move from 1.25V. Have a p0158 code 02 circuit high voltage. I'm leaning towards a clogged catalytic converter even though I don't have a p0420 code. I may have a bad ground with a reading of 23 ohms on the ground wire.
Great video and we’ll explained I have a psa citreon c4 1.2 eb pure tech reading downstream oxygen sensor reading too high watching that video tells me it’s the catylitic converter
how would the 1st O2 sensor readings be like when there is a vacuum leak near the intake manifold and while idle? should they stuck around 0.02v or oscillate around low values ?
(Thanks for the video!)
Great Video. Thanks! Quick question: , if Cat is plugged at 3:00, why it(O2S22) fluctuates? Thanks.
I have a Ford expedition 2002, V8 5.4L I replaced a pipe under the intake manifold, a heater hose connected to the water pump, change new intake, replace spark plugs, coil packs, O2 sensors
Now I have 2 codes p1152 and p1132 took it to get it diagnosed. I need to replace both front oxygen sensor first and erase the code. Run car until code turn off if the code comes on again I’ll need to bring it to dealer and replace computer.
السلام عليكم. فيديو جيد. واريد ان أسأل هل الخط المسطح يعبر عن خلل في حساس الاوكسجين
The Bad Cat signal period is different from the upstream. Shouldn't the downstream have the same period as the upstream? (How can the downstream hold steady for a while and then dip? What is the process?
great video simple and easy to understand
Gave you a thumbs up good simple video where I didn't have to stop my life and watch a 30min vid
Can the reading be done on a standalone o-scope?
I’m getting a stft of 99.2 on both banks downstream(stft b1+2,s-2…..99.2 steady) on my ford 4.6 2v 300k miles. Getting rough idle and power loss
awesome explanation thankyou
Thank you so much. Outstanding explanation.
My Forscan reading shows bank 1 sensor 1 reading in Current mA or Imped V. I don't have a reading in mV like your scan tool shows.I'm getting a P219A code, Lean bank 1, and the mA reading goes from 0.00 to -0.11, and the V reading is 1.02 to 1.01. Does this indicate a bad O2 sensor? Thanks!
Modern cars, the wide band O2 is before the CAT. Narrow band is after the CAT
I have 1 downstream steady at 0.6 and one steady at 0.1. Does that mean the low one is bad. It sometimes goes up in voltage but rarely.
2000 express 5.7. No check engine light. On a long pull hill o2 show good but engine stalls progressively worse as the van goes up the hill. New cats and air flow sensor. Like not getting gas. In use of scope what should I be looking at.
can you use these readings to find out if your o2 sensors are broken?
I have a issue with my 02 sensor 1 bank 1 in my Murano first replacement on it came out with a voltage of 2.4 to 2.8 so I got another one now this one is putting out 1.5 to 1.8 for what I can see I shouldn't be having any other issues but a bad sensor do you think I'm right both sensor I purchase from Amazon e and eBay we're around 60 dollars your knowledgeable opinion could crack this case pleas let me know Ifvyou think paying the 231 dollars at AutoZone will fix this issue
Can an O2 look normal percentage wise on a scanner but still be bad?
At 1:20 you say we should see switching multiple times per second. But the graph is switching much slower than that, about 2 seconds for a full up and down. Yet you say it looks like those sensors are normal. I have to say it sounds contradictory. Could you please clear that up for me?
My O2 sensor on bank 1 is showing 0 volts, but I have no error codes (2009 Honda Accord). Not sure what to think.
2014 Hyundai Elantra
1.8L
Consistent P0420 code
While looking at Sensor 2 reading, while driving on the highway, the voltage does switch some down to 0.1 volts but at idle it stays at 0.7 - 0.75 volts
Also, while driving at highway speeds, when I take my foot off the accelerator and let the vehicle coast, the voltage goes to 0.000 volts and stays there until I push the accelerator again. I'm unable to look at the upstream voltage. I'm using Blue Driver and it says the PID is unavailable
I'd like to condemn the post cat O2 sensor but I don't think I have enough evidence.
I have an O2 sensor that is constant negative value. Slowly going between -.09ma to -.05ma. Would this be a bad O2 sensor?
2012 Jeep Wrangler- I had a fault for bank 2 sensor 2, so with 130k miles on the Jeep, I replaced all 4 sensors. I am still getting the same p0158 fault code as before, so I hooked up my scanner and the bank 2 sensor 2 is showing a steady 1.275 volts that never changes, regardless of engine rpm or fuel delivery while the others fluctuate as normal.
I ran some Catacleaner through the Jeep as per the instructions on the bottle. I didn't expect a complete fix, but I wanted to see if it would at least open the cat up enough to show a change on the sensor data, which it did not accomplish.
I'm pretty much stuck now and don't really have the money to replace the cat, especially if that's not the issue. Would a bad wire or corroded ground cause the voltage to stay at a constant voltage like this?
Please help me, i used an ODB reader. The upper o2 is ok jumps up and down like in the video. The downstream stays almost straight but 100, 115 to 120.
I have a NOx absorber B2 fail
when i did a monitor test with a code reader
but i can't seem to find out what a NOx
absorber B2 is... i take it the B2 is bank 2
and the NOx is an oxygen sensor but
where is this... upstream or downstream.
i have a Ford Focus 2009 1.6 TDCI
any help would be highly appreciated 🙏
On my scanner hooked up to a Honda Element, I get O2S B1S1 in mA and Lambda B1S1 in a unit-less value. How do I compare with readings like yours in mV?
Great video 👍
Great explanation thanks
So how do you know if the downstream sensor is the problem or the cat is?
How do i get the snap on tool to display 2 graphs at one time
Excellent Instructional Video !!!
Question, i had a p0138 code. Replaced the sensor.
Then the sensor before the cat same side tripped code p0133. Any ideas?
Question, so my o2 sensor is just staying at 0.02v at idle, it can jump to a max of 4.9 when i rev it, so the data it's sending is faulty, but my question is, are there other factors that can make it rub such low voltage on idle, this is the pre-cat o2 sensor.
What vehicle is it on?
Question concerning a 2005 Honda Accord 3.0.....v6.....my bank 1 sensor 1 is barely reading 0.04 mili Amps.....and bank 2 sensor 1 is reading the same thing!! Is this the reason why my fuel trim is off? Computer tripped a p0171 code .....lean condition.
I have a 2000 tacoma v6. I recently had a p301 cyl 1 misfire and p0300 random misfire codes. Found a bad cyl 1 injector, replaced it and the code went away and check engine light disappeared.
A few days later, I get a new check engine code for p0420 catalyst below threshold bank 1 (my scanner doesnt say which sensor just says bank 1). I get my obd2 scanner and check live data and at idle my upstream sensor reads from 0.00 to 900, fluctuating in between every second like you described and the downstream sensor is slowly fluctuating from 3.254 to 3.300. Not sure what to make of this but if I understand what you're explaining is that my B1S1 (upstream before cat) is working properly and the B1S2 (after cat) is not?
Help would be greatly appreciated
Thank you for the information great video,
What if it intermittently follows the upstream and then goes back to normal.
Very clear and concise, thanks.
Awesome explanation ! Thank you
Is it possible that the 2nd downstream O2 sensor also bad (and/or)?
I probably would not condemn a CAT before testing the O2.
I thought stoichiometric readings only came from downstream o2? I have a sienna with pre cats, and the readings fluctuate but stay roughly the same number
Outstanding content, thank you.
How can you tell from number data that a sensor is bad?... 2003 camry sensor 2 while driving drops to 0 especially while accelerating is that normal or no? Getting a p0420 code just trying to rule out everything before replacing a cat
Awesome video and straight to the point. My question is on bank one I’m getting s1 between .01 and .90 and s2 between .030 and .810
On bank 2 s1 is .065 and .885 and s2 between .065 and .715
I am at my wits end with trying to complete the catalyst monitor and I can’t smog the vehicle
What do you believe the problem is, all your help is appreciated
Thank you
That tells you that you have bad cats. Thus the reason you cant complete the cat monitor. If the cats are working you would see a steady voltage reading on both secondary sensors.
Likely a bad o2 man. Or exhaust leaks between o2 sensors.
wish somebody would do this on wideband O2 sensors.
Is this the same for a high flow cat??? 99nb1 miata
I have a Nissan FG10 model, engine QG15 (DE) can I swap 3 wire 02 sensor for 4 wire sensor. If adviceable, what are the connection as it is less 1 wire?
Great vid, right to the point.
My upstream doesnt regulate past 400. Only down stream. I have black smoke from exhaust and rough idle. Would this bad sensor cause car stalling?
How would you determine if its the cat vs the o2 sensor that is bad?
Have a 2003 explore 4.0 with bank 1 sensor 1 reading between 0.00 and 0.780. Similar with bank 2 sensor 1 and scan tool is reading lean condition on both with a rough idle. What’s your thought?
could i ask a quick question , my sensor 2 was pegged at constant 1.27v , dash light on , i guessed the sensor was broken and replaced it , now its flickering around 0.1 v or so , so not following your example of a dead cat , could it still be the cat?
O2 sensor 1 doesn't look consistent. It could be lazy and on its way out
Are there any scan tools that instead of showing you a bunch of graphs, numbers, and abbreviations, it tells you a more meaningful conclusion such as "O2 sensor bad, please replace"?
Too many variables at play. Would be nice though.
Hey, my pre-cat is fluctuating every 5 seconds mostly hanging in the 0.7-8V range. I’m also getting a P0171 running lean code. No visible vacuum leak after smoke test. What could it be?
Is it normal for sensors to put out readings while off, overnight. My 17 GMC sierra bank 2s1 reads +1 and b2s1 reads +12 while off... thank you in advance
Hi what if the catalytic is the one problem. Should expect to see fluctuations graphic or just the flat line?
Very helpful. Thank you.
do you know why honda and acura cars dont support o2 sensor 1 .... but it do support 02 sensor2 ?
Hello, my Fiat Bravo 1.6 multijet is showing between 10-12 g/s on idle. I think this is too much for this engine? Also, sometimes the car idle is not stable and the rpm are moving. When I observe the MAF in that situation it is moving on idle between 1.5 - 13 g/s. Will cleaning the MAF with a spray will help? Thanks in advance!
Hi what is a normal reading number for bank 1 and 2?
My car getting .267 on bank 1 sensor 1 and .675. Flat
And same number on bank 2
But still have p0429?
Can you advice
Awesome video