Help: P0171 System too Lean (Bank 1)
#41
11-23-2009, 08:29 AM
It seems pretty odd that the GM electrical schematic (See attachment) shows 3 instances of HO2S, with two sensors on Bank 1, and only one on Bank 2? Looks like just it's just a bad representation of the one after the CAT.
So I captured some data on the O2s, and the O2 Sensor 1, Bank 1 regularly dips to 85, 95, 125 mV but also values in-range; the normal range is 200-800 mV -- so I think that is my smoking gun? The other sensor stays within the normal range.
You see, the failure has to be documented by the shop for the extended warranty to cover the part, as they only covered failed parts.
So I captured some data on the O2s, and the O2 Sensor 1, Bank 1 regularly dips to 85, 95, 125 mV but also values in-range; the normal range is 200-800 mV -- so I think that is my smoking gun? The other sensor stays within the normal range.
You see, the failure has to be documented by the shop for the extended warranty to cover the part, as they only covered failed parts.
Last edited by libertyforall1776; 11-23-2009 at 10:41 AM. Reason: Added Capture Mode information
#42
11-24-2009, 05:00 PM
Bank 1 is driver side. Bank 2 is passenger.
Our cars use a Y pipe so there aren't 2 post-cat sensors, only one.
Sensor 1 = Before the cat
Sensor 2 = After
Yes if your sensor dips below 200 mV then it's considered a "burnout" and covered by warranty (electrical malfunction of the part).
The code itself points you to exactly what the problem is. Because the PCM is still thinking that the O2 is working because it's still receiving signal but it's actually malfunctioning and showing the wrong reading causing the lean condition.
Next time just listen lol. No use in doing all that technical bull**** when you can prove it in 10 seconds by swapping the O2s from one side to the other...
Our cars use a Y pipe so there aren't 2 post-cat sensors, only one.
Sensor 1 = Before the cat
Sensor 2 = After
Yes if your sensor dips below 200 mV then it's considered a "burnout" and covered by warranty (electrical malfunction of the part).
The code itself points you to exactly what the problem is. Because the PCM is still thinking that the O2 is working because it's still receiving signal but it's actually malfunctioning and showing the wrong reading causing the lean condition.
Next time just listen lol. No use in doing all that technical bull**** when you can prove it in 10 seconds by swapping the O2s from one side to the other...
#43
11-25-2009, 12:15 PM
Well thanks for your help, but the Chevrolet Service Center's techs aren't doing the best troubleshooting, or the GM diagnostic process they follow doesn't cover enough ground.
The Ext. Warranty requires proof of failure to cover costs, and now I believe I have it. Also, I have seen the Bank 2 O2 sensor dip below 200 mV as well in live data, so I think it's bad too. If so, I don't think your test of swap would prove it. For some reason, the Autoxray EZScan 6000 Capture mode doesn't capture the Bank 2 O2 sensor, just Bank 1 and the one after the cat. I reported the bug to them and am awaiting an update.
The Ext. Warranty requires proof of failure to cover costs, and now I believe I have it. Also, I have seen the Bank 2 O2 sensor dip below 200 mV as well in live data, so I think it's bad too. If so, I don't think your test of swap would prove it. For some reason, the Autoxray EZScan 6000 Capture mode doesn't capture the Bank 2 O2 sensor, just Bank 1 and the one after the cat. I reported the bug to them and am awaiting an update.
Yes if your sensor dips below 200 mV then it's considered a "burnout" and covered by warranty (electrical malfunction of the part).
The code itself points you to exactly what the problem is. Because the PCM is still thinking that the O2 is working because it's still receiving signal but it's actually malfunctioning and showing the wrong reading causing the lean condition.
Next time just listen lol. No use in doing all that technical bull**** when you can prove it in 10 seconds by swapping the O2s from one side to the other...
The code itself points you to exactly what the problem is. Because the PCM is still thinking that the O2 is working because it's still receiving signal but it's actually malfunctioning and showing the wrong reading causing the lean condition.
Next time just listen lol. No use in doing all that technical bull**** when you can prove it in 10 seconds by swapping the O2s from one side to the other...
Last edited by libertyforall1776; 11-30-2009 at 11:34 AM.
#44
11-30-2009, 11:33 AM
So Bank 1 O2 Sensor was replaced, but oddly, the replacement sensor still dips below 200 mV. Isn't troubleshooting fun?!
#45
12-02-2009, 11:56 AM
The two System too Lean Bank 1 & 2 codes are still there after replacing Bank 1 O2 sensor... So now what?
I think it maybe fuel system related, injector problem, or vacuum related...
I think it maybe fuel system related, injector problem, or vacuum related...
Bank 1 is driver side. Bank 2 is passenger.
Our cars use a Y pipe so there aren't 2 post-cat sensors, only one.
Sensor 1 = Before the cat
Sensor 2 = After
Yes if your sensor dips below 200 mV then it's considered a "burnout" and covered by warranty (electrical malfunction of the part).
The code itself points you to exactly what the problem is. Because the PCM is still thinking that the O2 is working because it's still receiving signal but it's actually malfunctioning and showing the wrong reading causing the lean condition.
Next time just listen lol. No use in doing all that technical bull**** when you can prove it in 10 seconds by swapping the O2s from one side to the other...
Our cars use a Y pipe so there aren't 2 post-cat sensors, only one.
Sensor 1 = Before the cat
Sensor 2 = After
Yes if your sensor dips below 200 mV then it's considered a "burnout" and covered by warranty (electrical malfunction of the part).
The code itself points you to exactly what the problem is. Because the PCM is still thinking that the O2 is working because it's still receiving signal but it's actually malfunctioning and showing the wrong reading causing the lean condition.
Next time just listen lol. No use in doing all that technical bull**** when you can prove it in 10 seconds by swapping the O2s from one side to the other...
#46
12-02-2009, 02:56 PM
This code is caused by the O2 sensor reading too much oxygen in the exhaust, but that doesn't mean the O2 sensor is to blame for the problem. It sometimes is, but it's most often caused by a dirty or malfunctioning MAF sensor. If it's dirty, it will tell the ECM/PCM that it's not getting enough air, so it opens the IAC further to let more air into the engine.
Pull out your MAF (if you've got the 3.8L, it's near the back of the intake manifold on the passenger side). If it's dirty or oily, clean it with electronics cleaner or brake cleaner (not carb cleaner, because it can damage the circuitry), let it dry, and then slap it back in there. Also, check its wiring.
You can also test the terminals for correct resistance, etc (check your manual or ask your mechanic for what the numbers should be).
I don't know if those are covered under your warranty or not, but if not they're cheap at AutoZone. Hell, I might even have an extra one lying around I could mail to you, LOL. I grabbed a few extra sensors last time I was at the junkyard, just in case any of them were causing my past problems.
It could also be a dirty fuel filter or a cracked vacuum hose. The worst problem these cars have is that the rubber hoses and hose-connectors always deteriorate because of the alcohol that's in almost everyone's gas these days. Plant-based fuels (even biodiesel) corrode rubber like crazy.
It's possible, but not likely, that there's a vacuum leak at the intake manifold gaskets or bolts. I would check the MAF and hoses first, though. If it's anywhere close to time, I'd change the fuel filter as well. I waited too long on mine last time, and it was horrible... LOL.
#47
12-02-2009, 08:38 PM
The car has only about 61k mi., and the only drivability issue is a little rough idle. I still need to spray the MAF/Butterfly, just cleaned the air filter, and gotta check the PCV.
One thing to note, I have the SLP CAI and Whisper Motorsports lid -- I will sure be mad if they are somehow causing the lean condition! I wonder if since 1 coil pack was replaced, and 1 injector replaced that could now be indicating other coils and or injectors need replacing? Funny thing is, there is no misfire codes...
At what mileage did you finally change your fuel filter? We should all cut into our fuel filters when we change them and post the picture along with the mileage to help the rest of us learn...
One thing to note, I have the SLP CAI and Whisper Motorsports lid -- I will sure be mad if they are somehow causing the lean condition! I wonder if since 1 coil pack was replaced, and 1 injector replaced that could now be indicating other coils and or injectors need replacing? Funny thing is, there is no misfire codes...
At what mileage did you finally change your fuel filter? We should all cut into our fuel filters when we change them and post the picture along with the mileage to help the rest of us learn...
If your system is lean, it's DEFINITELY either too much air or not enough fuel. Are there any actual issues noticable while driving? Is there any knocking, loss of power, or hesitant/surging accel? Often times you won't notice any symptoms, but it helps to know the big picture before giving advice. Details are always good.
This code is caused by the O2 sensor reading too much oxygen in the exhaust, but that doesn't mean the O2 sensor is to blame for the problem. It sometimes is, but it's most often caused by a dirty or malfunctioning MAF sensor. If it's dirty, it will tell the ECM/PCM that it's not getting enough air, so it opens the IAC further to let more air into the engine.
Pull out your MAF (if you've got the 3.8L, it's near the back of the intake manifold on the passenger side). If it's dirty or oily, clean it with electronics cleaner or brake cleaner (not carb cleaner, because it can damage the circuitry), let it dry, and then slap it back in there. Also, check its wiring.
You can also test the terminals for correct resistance, etc (check your manual or ask your mechanic for what the numbers should be).
I don't know if those are covered under your warranty or not, but if not they're cheap at AutoZone. Hell, I might even have an extra one lying around I could mail to you, LOL. I grabbed a few extra sensors last time I was at the junkyard, just in case any of them were causing my past problems.
It could also be a dirty fuel filter or a cracked vacuum hose. The worst problem these cars have is that the rubber hoses and hose-connectors always deteriorate because of the alcohol that's in almost everyone's gas these days. Plant-based fuels (even biodiesel) corrode rubber like crazy.
It's possible, but not likely, that there's a vacuum leak at the intake manifold gaskets or bolts. I would check the MAF and hoses first, though. If it's anywhere close to time, I'd change the fuel filter as well. I waited too long on mine last time, and it was horrible... LOL.
This code is caused by the O2 sensor reading too much oxygen in the exhaust, but that doesn't mean the O2 sensor is to blame for the problem. It sometimes is, but it's most often caused by a dirty or malfunctioning MAF sensor. If it's dirty, it will tell the ECM/PCM that it's not getting enough air, so it opens the IAC further to let more air into the engine.
Pull out your MAF (if you've got the 3.8L, it's near the back of the intake manifold on the passenger side). If it's dirty or oily, clean it with electronics cleaner or brake cleaner (not carb cleaner, because it can damage the circuitry), let it dry, and then slap it back in there. Also, check its wiring.
You can also test the terminals for correct resistance, etc (check your manual or ask your mechanic for what the numbers should be).
I don't know if those are covered under your warranty or not, but if not they're cheap at AutoZone. Hell, I might even have an extra one lying around I could mail to you, LOL. I grabbed a few extra sensors last time I was at the junkyard, just in case any of them were causing my past problems.
It could also be a dirty fuel filter or a cracked vacuum hose. The worst problem these cars have is that the rubber hoses and hose-connectors always deteriorate because of the alcohol that's in almost everyone's gas these days. Plant-based fuels (even biodiesel) corrode rubber like crazy.
It's possible, but not likely, that there's a vacuum leak at the intake manifold gaskets or bolts. I would check the MAF and hoses first, though. If it's anywhere close to time, I'd change the fuel filter as well. I waited too long on mine last time, and it was horrible... LOL.
#48
12-03-2009, 07:07 AM
My brother-in-law said he replaced the fuel filter at 275k miles (about 5k before I bought it from him). Came to find out that he didn't actually replace it... just bought one and had it sitting in his garage. I replaced it at 287k, so about 12k miles later than it needed. It was dripping this nasty, black mess... I'm surprised my fuel pump didn't fail.
Your manual should tell you at what intervals to change the fuel filter. I'm pretty sure it's every 15k miles, but it might be 30k.
You might also want to check your PCV valve if you haven't already. I clean mine every time I change the oil (with seafoam), and I've never had to replace it.
Your manual should tell you at what intervals to change the fuel filter. I'm pretty sure it's every 15k miles, but it might be 30k.
You might also want to check your PCV valve if you haven't already. I clean mine every time I change the oil (with seafoam), and I've never had to replace it.
#49
12-03-2009, 10:43 AM
Funny, the ONLY mention of fuel filter in the Owner's Manual is the part #s:
Fuel Filter
3800 V6............. . G627*
*ACDelcoR part number.
Does anyone have any GM document that states the Camaro fuel filter service interval?
Fuel Filter
3800 V6............. . G627*
*ACDelcoR part number.
Does anyone have any GM document that states the Camaro fuel filter service interval?
My brother-in-law said he replaced the fuel filter at 275k miles (about 5k before I bought it from him). Came to find out that he didn't actually replace it... just bought one and had it sitting in his garage. I replaced it at 287k, so about 12k miles later than it needed. It was dripping this nasty, black mess... I'm surprised my fuel pump didn't fail.
Your manual should tell you at what intervals to change the fuel filter. I'm pretty sure it's every 15k miles, but it might be 30k.
You might also want to check your PCV valve if you haven't already. I clean mine every time I change the oil (with seafoam), and I've never had to replace it.
Your manual should tell you at what intervals to change the fuel filter. I'm pretty sure it's every 15k miles, but it might be 30k.
You might also want to check your PCV valve if you haven't already. I clean mine every time I change the oil (with seafoam), and I've never had to replace it.