The ones I've observed fail such that the car will idle at a very high (1200+) RPM. Unplugging the module will return the idle to about 800 but it will NOT be regulated, i.e. it will idle faster when hot, slower in gear (auto) etc. If everything is operating normally and the temperatures are not too extreme, the car actually operates pretty well without it. (Hi Bill). Dave S -- In dmcnews@xxxxxxxxxxxxxxx, doctorDHD@xxxx wrote: > Does anyone have the schematic for the idle speed ECU? > > Do they fail in any particular modes? > > Thanks > > Dave > 6530