Circuit/System Description

The engine control module (ECM), based on information from various sensors, determines the desired engine speed. The ECM monitors the crankshaft position (CKP) sensor and the transmission output shaft speed sensor to determine when an engine idle condition is present. When the engine is idling a desired engine speed is determined by the ECM. When the actual engine speed exceeds the desired engine speed, a DTC is set along with a reduced engine power mode.