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
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.
2005 Chevy Cobalt P0171 Lean

More Car Repair Help

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 alarm.

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.