My son's 240 turbo is continuing to experience a high idle (roughly 2400 RPM). It was intermittent, but now seems to be a full-time problem. I've run all of the CIS trouble-shooting steps in the Bentley manual; the car also has a good engine harness (thanks Dave Barton!), including the "pig-tail" that runs to the ECU on the passenger side of the engine compartment. It also has a new Bosch idle air controller and in-head temp sensor. I can feel the idle controller vibrating when the engine is running, but seems to be less than usual. I'm thinking that maybe the ECU is only sending the "open" part of the output signal (to the IAC--either to terminal 3 or 5, but not both). Could I check this with a DVOM at the ECU while the car is running?

Bentley says that if everything else checks good, it's likely the ECU that's bad. The ECU for the idle controller is Bosch part number 0 280 220 005, but they seem to be getting pretty rare. Does anybody know of somebody that rebuilds these things? I guess my other option is to post a "wanted" in the classified section . . . .

Thanks in advance!

Steve A-