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'02 Chevy PU Service Engine Soon Light

My '02 1500 Chevy PU shows trouble codes 0171 and 0174. It appears that the codes are dependant upon ambiant temperatures and the temperature of the vehicle. Is the fix to change o2 sensors?

Could be a intake air leak that’s allowing air into the engine that’s not being being read by the MAF sensor, causing a lean condition. Any Modifications to the intake?

I don’t think it is an air intake issue. I have checked this issue by spraying carb cleaner around the manifold and the engine rpm’s didnot change.

Try cleaning the Mass Air-Flow sensor with the proper solvent.

If the MAF sensor is contaminted with debris, it will read less air entering the engine than what the O2 sensors measure. And it will trip this code.


I’ve checked the MAF for debris and cleaned with a soft cotton cloth. These codes set after the truck has been driven, achieved running temperature, is shut off and restarted after a period of time but before it has completely cooled to ambiant.

No, he said you need to use the spray MAF cleaner. A wipe won’t clean the element. I second his opinion.

OK guys, I bought a can of CSR MAF cleaner, removed, cleaned and reinstalled the MAF sensor. No good, the SES light came on and showed the 0171 &0174 codes. This issues really seems to be temperature related. If the vehicle is cold, ambiant temperature is approximately 60 degrees, it will nopt set a code. If the vehicle is shut of and restarted, a code id set.