P0506-07, P1506-07
IDLE SPEED CONTROL SYSTEM - ISCFig. 1 Idle Speed Control Valve (B-Bank):
Monitoring Procedure
This diagnostic operates only once per trip, during the first long duration hot idle period after engine start. The diagnostic works by changing the position of the idle speed control valve on each bank in turn. If the engine RPM or manifold pressure does not change as expected then a failure judgement is made. The actual engine RPM is compared to the target speed that the ECM is trying to achieve, to determine which diagnostic trouble code (DTC) will be set. The appropriate DTC is stored if the failure judgement is made on two successive trips.
ECM Interface Circuit:
