Car Experts: Check Engine

[FDWxMan]

Check engine light came on coming home from work today.

Code is P0171 "System too lean Bank 1" on my Corolla.

Most of the internet chatter seems to point at faulty or dirty MAF sensor, or O2 sensor issue. I'm not really experiencing any of the typical problems with stuff in that area (loss of power, etc) so everything seems to be driving fine.

Had bad O2 sensor on an old car and it was obvious driving, not the case this time.

Is it possible this could be in anyway related to the cold? First time it's had to sit out in the single digits all year, and it was a little slow starting when I left work.

[JSmoove]

Ive been chasing this problem with my BMW for half a year now. It could be a vacuum leak that's the problem. Since its starting to get cold your intake hoses might have finally cracked due to old age and this latest cold snap may have been the last straw.

When i got this code I went out and checked and a lot of my intake hoses (sometimes called boots) had huge cracks in them and the engine wasn't getting the right vacuum pressure.

Does your car shake or stumble at all initially?

[FDWxMan]

Ive been chasing this problem with my BMW for half a year now. It could be a vacuum leak that's the problem. Since its starting to get cold your intake hoses might have finally cracked due to old age and this latest cold snap may have been the last straw.

When i got this code I went out and checked and a lot of my intake hoses (sometimes called boots) had huge cracks in them and the engine wasn't getting the right vacuum pressure.

Does your car shake or stumble at all initially?

Haven't noticed anything performance-wise that would indicate a problem. Everything sounds/feels just fine to this point.

[JSmoove]

Well like I said before. It could be a number of things. You can lose your mind chasing vacuum leaks. Hell I still haven't figured out mine yet.

Maybe all you need to do is go to your local Autozone or something and get a can of MAF cleaner. Its about $6 a can. BMW's are not exactly known for being easy to work on and this job was super easy so I cant imagine it would be tough on your Corolla.

Let us know what shakes out.

[Cyclonesrule91]

At times changes in temp and humidity will make the O2 sensor code. If it's running fine give it a while and chances are it will go off.

[Cyclonepride]

At times changes in temp and humidity will make the O2 sensor code. If it's running fine give it a while and chances are it will go off.

So in a roundabout way, it's his own fault?

[CYCLONE STATE]

Check engine light came on coming home from work today.

Code is P0171 "System too lean Bank 1" on my Corolla.

Most of the internet chatter seems to point at faulty or dirty MAF sensor, or O2 sensor issue. I'm not really experiencing any of the typical problems with stuff in that area (loss of power, etc) so everything seems to be driving fine.

Had bad O2 sensor on an old car and it was obvious driving, not the case this time.

Is it possible this could be in anyway related to the cold? First time it's had to sit out in the single digits all year, and it was a little slow starting when I left work.

Very common problem with Corolla and Matrix. If it set the code P0171 when outside temps are very cold it will very likely need a new intake manifold gasket. The part has been redesigned and is about $10. It takes about an hour at the most to install. Toyota issued a TSB (technical service bulletin) about this problem.

If you have any questions let me know!

[psychlone99]

At times changes in temp and humidity will make the O2 sensor code. If it's running fine give it a while and chances are it will go off.

Correct. Had this happen in my car with the first big change in temp this winter. I waited it out because I wasn't noticing any problems and couldn't diagnose anything myself, and it went off after a few days.

Seeing that your here in DM, this big drop in temp the last few days may have triggered it. If your car is running fine, wait it out a bit.

[FDWxMan]

Very common problem with Corolla and Matrix. If it set the code P0171 when outside temps are very cold it will very likely need a new intake manifold gasket. The part has been redesigned and is about $10. It takes about an hour at the most to install. Toyota issued a TSB (technical service bulletin) about this problem.

If you have any questions let me know!

Thanks, looks like an easy enough one to check.

[hawkadoodledoo]

Thanks, looks like an easy enough one to check.

You could always go to Aamco, where they do a free diagnostic check, and they can tell you exactly what is wrong with your car.

[kingcy]

As long as it is not flashing and you car is running fine i wouldnt worry too much. If you are worried go in and have someone clear your codes.

[CyCrazy]

I have ignored my check engine light for almost 2 years, I treat it like the seatbelt light that blinks for 2 minutes.

[Hawkeye11en1]

I have ignored my check engine light for almost 2 years, I treat it like the seatbelt light that blinks for 2 minutes.

I know someone that will pull your *** over and put you in fail for that ****, pal.

[cyspy]

Just put a piece of black tape over the check engine light on your dashboard and that should solve all your problems.

[Yellow Snow]

Try this...

Unhook your battery....

Re-connect your battery after... i don't know... 5 minutes or so.

Fire that baby up. If the light comes back on you need to sacrafice a virgin. OR do what the other guys in this thread recommended.