Error Code P0101 and Idle Air Controller

[BNaylor]

Thanks for the feedback mbhudd and congratulations. Did you at least try cleaning the IAC before replacing? Actually the P0101 DTC was telling you the general area to look at and was not indicative of solely a bad MAF sensor. That requires proper troubleshooting and a good course of diagnostics based on either experience or proper documentation like a GM FSM. However, having said that and contrary to belief a bad IAC or an IAC giving high IAC counts will cause a MAF system/range/performance problem and may show as a P0101 or P0102 DTC. MAF, MAP, TPS, PCM module, dirty throttle body, etc. are other possibilties but possibilities only. Based on what I see sometimes you have to go through all the possibilities before finding the actual culprit so don't feel bad or alone unless you get lucky and hit it on the first try.

Incidently, one of the tests for MAF troubleshooting per the GM FSM is to command the IAC valve to extend fully which will give zero IAC counts. The MAF low frequency and/or range tests are dependent on a proper idle. An IAC driver test fixture J37027 is normally used as part of the diagnostics but not all mechanics or DIY'er have the fixture readily available in their tool boxes.

Therefore, IMO a bad IAC is both plausible and feasible as it pertains to your specific problem.