SES on 2006 Chevy Cobalt.
2.2 L 4 cylinder
Check engine light

Question = The check engine light is on in my 2005 Chevrolet Cobalt 4 cylinder. Is this something to worry about. The car runs just fine and starts good. Any damage if keep driving like this. I am out of work and really cant take to a shop to tell me what is wrong, then sell me a bunch of parts and service. Thanks for any help.

Any time a check engine ( SES ) light comes on the dash, the computer system is  seeing a problem in one of the emissions or other systems. When the light comes  on, a 'Trouble code' is stored in memory. Even  if the light goes out, the code is still in  the  PCM (Powertrain Control Module).

There are many, many things that cause this light. The first step is to have the system  
scanned for codes with a code reader. This can be done for free at many of the large  national parts store chains. Then diagnostics of the system needs to be performed.  Just because a code is related to a particular sensor, does not mean that senor is  faulty. Many things can cause codes to be set for a sensor or system that is not related  to the codes set. Example: an oxygen sensor codes does not necessarily mean the  oxygen sensor is bad. The problem could be with another sensor, misfires, vacuum  leak, fuel quality, etc.
Todays GM vehicles use many sensor, switches, solenoids, and other  electrical components to control or monitor every aspect of the engine.

From controlling the fuel and ignition systems, to monitoring the emissions.
A problem in any of these systems, or subsystems, can cause the check  engine light to come on.
2009 Chevy Cobalt 2.2 ecotech.
Warning lights- engine power reduced. Codes P0641 MAP sensor MAF sensor. How to trouble shoot which sensor is open?
You will need a schematic and a
volt meter to do the proper testing. P0641 is for the 5 volt reference for these sensor and a few others. You would need to test for 5 volts getting to the sensor. If the voltage is low, disconnect sensors one at a time until you see the voltage go back to 5 volts. If there is no change, then you have an open circuit and would need to do a resistance check from the PCM to each sensor connector.
2006 Chevy Cobalt Engine Light Codes For MAP And MAF Sensors

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