Hey, I'm having an issue where my PCM doesn't read IAT input for about 15-18 minutes. It sits at -31 then after time it all of a sudden starts to read like normal. Its very aggravating & since I'm on ethanol its idling excessively rich.

I've checked my wiring about 200 times & its all correct & the connections are good. I thought maybe the sensor is bad but why would it start working after a certain amount of time?

Is there any setting on the PCM I can check via HPTuners?

 

Get a new GM sensor and see if it helps. If not return it....

 

another IAT sensor tried and still the same results.

 

Have you recently written a calibration using HPT4? Reason I ask is I am dealing with a PCM that will not command fans on but fans work and relays work when jumpered. Wondering if it's a bad pcm for stupid reasons or a bad pcm for HPTuners reasons.