Hi, Has anyone else encountered check engine code P0171? My 08 coupe has about 700 miles and my check engine light came on. Brought in to dealer and the said that code is associated with Heated 02 Sensor. Service Tech said he tested vehicle, found no issues with any of the parts that the sensor monitors, and reset. Dealer states that GM is aware of issue but that they do not have a fix yet. Dealer tells me to ignore future Check engine lights until fix is completed by GM or to bring in to them if it happens again. Well here we are, the second time I take it out, I receive the same check engine light. Any ideas?

 

Okay, first a disclaimer, my experience is with a different brand of car...

My Jag XJR had the same problem, and the heated O2 sensor was, indeed, bad. Although I did not notice much difference in the way the car drove, after the O2 sensor was replaced, the difference was night and day. I would not accept any advice that said 'ignore the code'.

For one thing, your car would never pass a smog test (if required), because that is an emissions related code. Second, based on my experience, the performance will be affected. At the least, the fuel mixture will be wrong with the computer trying to account for the error in the O2 sensor.

 

That code is for Fuel Trim too lean on bank 1. So the sensor, wiring, ecm... is working, but that bank is reading too lean.

There is a bulletin for 08 Vettes getting both P0171 and P0174 intermittently. That bulletin says to first do all the diagnostics for basic lean condition or vacuum leak. Then if nothing is found, wait for further information (bulletin update) as it is being investigated.

Yours doesn't sound so intermittent, since it reset right away, and your not getting both codes. Only one bank is involved with your condition.

I think your dealer needs to do more than just erase the code. The bulletin says to check for a vacuum leak and to perform the complete diagnostics for that code.

The O2 sensor could be ruled out pretty easy by swapping banks and see if P0174 shows up instead. If its still throws P0171 with the O2 banks swapped, then I'd be looking at why that bank is running lean.
The manual says to look for vacuum leaks in the fuel injector O rings, throttle body, manifold, evap system... Then fuel system checks, such as injector balance tests looking for a clogged injector.

I'll bet something will be found, such as a vacuum leak or clogged injector. There are enough 08's running around without setting that code for me to believe, this dealer need to do more diagnosis.

 

This is the C5 diagnostic codes. I don't know if they have changed for C6.

http://forums.corvetteforum.com/show....php?t=1514518

 

Wow-- very thorough and well informed answer!

Hope it helps the OP . . .certainly better info than his dealer provided!

 

Try a gas station with more power in the product: e.g. don't use cut-rate station gas, use BIG brand name. Reason had truck with same problem, put my code reader in dash conn got same code ..got off 85 ethanol back to a beter grade of reg...bingo no more false readings. good luck...Happy St. Pats day

 

If it is stock I'm probably gonna say a bad 02 sensor or possibly a vacuum leak. If it isn't stock and has headers I'd say it needs a tune to ignore the rear 02 sensors. Or if you have a CAI I've read some posts that I guess people have airleaks or something with the MAF. So if you have anything aftermarket I'd consider a tune. If it is stock take it back and demand a solution because you didn't pay 45Kish for a CEL that you have to ignore. My 2cents.
-David

 

Without a doubt the owners and vendors on this forum are the most knowledgable automobile people on this planet....even the ones from Jersey who don't wave....

 

HI Mitchrider,

Thanks so much for the informative response. I called tech before i read this response to tell him I am bringing car in and during our conversations, there was mention that two codes were set off. I unfortunately did not get the other. I will get when I bring car in tonight. You wouldn't happen to know what the TSB for this issue is and the website where I also could investigate?

 

Thanks Talldude. I have been using only premium at Shell. Happy St. Patrick's day to you too!

 

There are times that I am so darn proud of the information that is posted here for a member who has a legitimate question......and this is one of those times!!!!!

 

to some points. I work at a dealership. When we have a service bulletin like this, normal diagnostics is usually performed. A root cause is not always found. And the bulletin states that engineering is aware of the concern (which means there are many out there with this concern) and under investigation (engineering is not even sure what the cause is) When root cause is determined by engineering, a revised bulletin will follow with a fix.I doubt its a clogged injector being a 08 and low mileage. Just my .02 cent

 

Info in this thread, see post #26 for bulletin number:

http://forums.corvetteforum.com/show...ighlight=p0171

Detailed info here:

http://www.ls2.com/boggs/dtcs/DTC%20P0171.htm

 

If when you go back in you do find out that it is setting both codes P0171 and P0174, it may be a good chance that it is exactly what the bulletin is talking about and just something they will have to come out with a new calibration for. If it's just that one code, and it resets right away, I'd still lean toward something may be causing that like a vacuum leak, injector, map, maf... A tech can watch the Fuel trim on the scanner and if that one bank is out of whack, something has to be causing it.

 

Reoccurring CEL problem showing up on several cars in S. Texas and Arizona. Mine has come on 7 times in first 2500 miles. Pulls both codes for banks running lean. Dealer did all the TSB tests and checks with no faults found. BG was notified and I have been running different tests for them on my '08. The power train group thinks this is a fuel issue. I have documented Shell and ExxonMobil fuels used with others who have had lights come on. Currently running Chevron and have gone farther without a CEL then ever since buying car.

assumed you are in AZ but fill out your profile or send me a PM and I will keep you informed on progress.

 

Reoccurring CEL problem showing up on several cars in S. Texas and Arizona. Mine has come on 7 times in first 2500 miles. Pulls both codes for banks running lean. Dealer did all the TSB tests and checks with no faults found. BG was notified and I have been running different tests for them on my '08. The power train group thinks this is a fuel issue. I have documented Shell and ExxonMobil fuels used with others who have had lights come on. Currently running Chevron and have gone farther without a CEL then ever since buying car.

I'm in AZ get code PO 171 on my 2005 with 17.000 mi.A4.
running Chevron/ QT, only???? code clears after 5 or 6 start ups.
NW, Valley dealer checks and found nofaults.

 

I am in AZ as well.. 2500 miles and have had both codes show up 5-6 times. After 3 cold starts the CEL goes off. Took it to dealer and they told me of the service bulletin from Chevy.

I have been in communication with a member in Texas who has tried to contact Bowling Green... They told him to use "better" fuel. I have been running one of their "approved" brands and still had the codes show up. It is annoying. Nice thing is that you can do the diagnostics with onstar when it happens this way that you know it is not a real problem

 

Any word from the dealer!!

 

Bringing car in tonight for service tomorrow. I did find out that two codes set off CEL P0171 and P0174. I will let you know what they say tomorrow.

 

Codes P0171 and P0174 were the two codes that went off again. They were reset. Tech said he did check all systems affected and found all working correctly. Tech stated that he did register as the issue again and spoke to GM directly. Unfortunately nothing new was revealed.