So I'm troubleshooting a Crossfire motor, that's had multiple issues. At this stage, I'm getting good feedback on the scan tool from the ECM (stock) but not getting any action on the two IAC's. Following the shop manual procedures, a test light between the connector pins and ground while in Field Service Mode (confirmed, as other components engage) yields no light on any of the pins. The IAC's are recent replacements, and all coils yield about 48 ohms. Has anyone seen this? I also swapped in the known-bad ECM (which is giving me incorrect outputs for the CTS and TPS) and no change. I guess it's possible I have a bad driver in both ECM's but any advice is appreciated. Thanks, and stay well.

 

My advice is be sure the wiring doesn't have any gremlins in it. Hook two of the wires together then on the IAC side then ohm it out on the ECU side. Not much other to say than yeah it could be the driver in the box.

 

Definitely looks like a driver failure, on an otherwise nice condition ECM. Does anyone have a source for repair, other than the parts stores?