Problem with GM stepper motor

[fuelie74]

I installed a MS3Pro in my car and finally got it running right about a month ago. Then the car sat while I did other work to it. Everything seemed to be ok till yesterday when I went to start it and it wouldn't idle. I have tried a different IAC with no improvement. Then I checked for AC voltage while running the test on it and got no voltage. Then I switched off the IAC and turn it of in advanced engine settings like described at the diyautotune.com and had no voltage. Could the driver itself of really died already? Am I missing anything else to check? I uploaded my current msq file, please note that I turned off the IAC after having problems and turned the screw on the throttle plate to adjust idle so I could drive it.

[Matt Cramer]

First question - where do you have the MS3-Pro logic ground wire connected?

[fuelie74]

All of the grounds for the megasquirt are connected to the engine.

[Matt Cramer]

If you cannot get 12V out of the IAC wires while using the IAC outputs in on/off mode, email us at websales@diyautotune.com - it sounds like the circuit may be damaged.