2005 Chevrolet Cobalt SES comes on.
Have codes = p0171 lean.
Why does my check engine light come on. I took my Chevrolet  cobalt to auto zone to have them
scan the computer because the
check  engine light was on. They said the OBD2 pcm code was
p0171 lean. What does this mean. Do i need an oxygen sensor or is there another problem. Why
does my check engine light come on. Thanks.
There are a few reasons for the code p0171 lean condition on this car and engine. It is possible
that the
oxygen sensor is bad, but m ore common is that the air intake cover is loose and leaking
vacuum to the throttle body assembly. This is the large black plastic engine cover on the center
of the engine. If the air filter has been checked recently, or had an oil change done where
someone checked the air filter, then they may not have gotten the cover on the throttle body
correctly, causing a lean condition and code.
Another common thing to correct this is that there is a PCM
(powertrain control Module) software programming update to correct a false p0171. This would
need to be reprogrammed with a dealer scan tool. These condition also apply to the chevy HHR,
Malibu, Pontiac pursuit, and Saturn Ion.

2007 Chevy Cobalt.
Replaced temperature sending unit for engine and new control head on dash for heating and
A/C. When engine temp does not read out on multifunction read out on dash ac compressor will
not turn on .What could cause this?

If you've got a bad thermostat, such as stuck open and the engine can't reach operating
temperature, or stuck closed and the engine runs hot, the air conditioning system will default to
off until the problem is fixed. I'd recommend doing a scan of the car's computer. Even with no
check engine light on, you may have set a code for a temperature problem.

Usually when this happens the temperature gauge, or display in your case, will not function and
the car's fans will run constantly. If you're experiencing this as well, then you know the thermostat
is to blame. If that doesn't seem to be the case, I'd still recommend getting a scan done where
you can actually see if the air conditioning is being commanded on or not from the car's
computer. That might help lead in a direction of proper diagnosis.
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2005 Chevy Cobalt P0171 Lean
Live Chat:

Question: You know anything about 2005 Chevy Cobalt engine light issues?  It goes on and off for no apparent reason.. car seems to be
running fine.  CD player not working right and key fob broken so alarm goes off (how do I turn that off or replace fob?)  Any ideas?

Answer: Is the engine light flashing or just comes on for a while, then goes off?

On solid just on and then off for a while... had a mechanic look at it a while ago-- he said nothing is really wrong and to only worry if it is
flashing... seems kinda weird advice to me though. Can the CD player being messed up cause the engine light to come on?  It seems kinda
far-fetched, but it is the only thing that has really been a recurring problem.

Yes, weird. If the check engine light is on, there is a code stored in the computer showing what system is having a problem. The CD player
not working right is internal to the radio. The alarm going off could be a module having a problem wheather it be the factory or non-factory

Everything is factory-- how the car came.  We can't afford a new car, and I don't feel comfortable driving around with the engine light on.
They mechanic turned it off, but it came back on and then was off for a while... recently had the ignition switch replaced (the recall) and it was
off before I brought it in and then on after they fixed it.

He turned off the light by just clearing the memory of codes from the computer- that is not a fix. It is is running OK, i would not be afraid to
drive it. There are over a hundred codes that can be stored- most are related to the emission system- which will not effect how it runs or
starts. I would suggest talking it to another mechanic to have the codes scanned.

Thanks, will do.