Is my ECM Toast?

[XfireZ51]

Originally Posted by gbmidyear66

Dom, regarding the IAC values - yes something is not 100% right here.

When I can get the idle to behave, car runs at about 775 RPM with IAC=0, if I turn on the A/C, it runs at about 725RPM with IAC about 13 or so(from memory). I agree - with A/C off I should not see IAC = 0 and 775 RPM.

The above implies a "leak ", but I don't think it is the typical situ with air leaking in from various hoses/tubes, etc given that I can stall the engine by blocking the throttle body.

I started out thinking I had an issue with a sticking throttle plate(s) - but the SES indicator and CAGS no longer working led me to suspect the ECM.

The IAC counts should be somewhere at 10-20 at idle. I think mine are at about 5-10. A/C should require more IAC steps to deal with drag of compressor. Again, it could imply a leak but if the IAC is opening up when AC compressor is on, it could be the Min Air adjustment. That would be consistent with the stalling motor when blocking TB. As for the SES light, are you saying it does not come on with ignition ON only, no engine run?
If you close up the throttle blades and see the IAC counts increasing, then there's no vacuum leak.