2005 Chevy Cobalt P0171 Lean

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.

Chevy Cobalt

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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.

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.

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