Circuit Description

This ignition system does not use a conventional camshaft position (CMP) sensor that detects valve train position. The ignition control module (ICM) detects when the #1 or #3 cylinder has fired on the cylinders compression stroke using sensing circuitry integrated within each coil. The sensing circuit detects the polarity and the strength of the secondary voltage output. The higher output is always at the event cylinder. The ICM sends a CMP signal to the engine control module (ECM) based on the voltage difference between the event and waste cylinder firing energy. This system is called compression sense ignition. By monitoring the CMP and crankshaft position (CKP) signals, the ECM can accurately sequence the fuel injectors. If the ECM does not receive a CMP signal from the ICM, DTC P0340 sets.