2001 Pontiac Grand Am 2.2L Ecotec.
Question : My Pontiac has the check engine light on. I had the a scan of the codes from Autozone and the mechanic said it was P0171 lean exhaust system. The traction control light is also on the dash. He said the code could have also set the traction lights. Car seems to run and idle good.
Starts up just fine all the time. What is a common cause for this problem? Can it be something i can fix my car myself. My boyfriend has tools and can do some work and maintenance. Thanks for any help.
Answer: Actually, a P0171 code is a Fuel Trim Lean code. The engine is getting more air than fuel which causes a lean condition and will set the code. A vacuum line that has come loose can cause this, or not having an air filter installed, or possibly the duct work to the throttle body has come detached.
Those are some quick fixes and can be checked easily. Other things that are a bit more involved to check would be a fuel injector that is clogged, fuel filter that is clogged, or even a fuel pump that isn't putting out as much fuel as it should. Those would need checked by someone experienced and preferably someone that has a scanner that can watch the data stream and fuel trim levels. Another possibility is a faulty oxygen sensor. I would check for vacuum leaks first, as that's usually the cause.