>Checking for voltage on the plug that connects to the Idle Speed Motor is a good start, but it's not everything that you need to do.< Yes, quite true. But I must point out that there will *always" be 12 vdc on that one pin to the idle motor, even it the ECU is not working. Checking for power there is pretty usless, especially if you reference it to another ground. This is because the ECU sinks current to the motor, it switches the two grounds. The plus side is wired directly to the motor internally through the ECU, checking for it is of only minor importance. Or just do what those who can't repair it say: Yank the idle system completely off and make the car "better" than it was designed to be ;)