Electronic Ignition System Diagnosis

ELECTRONIC IGNITION SYSTEM DIAGNOSIS















Circuit Description
The ignition system uses a ignition control module (ICM) for each bank. The ICM consist of a controller and ignition coils. The assemblies are mounted in the center of each camshaft cover, with short boots connecting the coils to the spark plugs. The ECM primarily uses engine speed and position information from the crankshaft (CKP) and camshaft position (CMP) sensors to control the sequence, dwell, and timing of the spark. The ECM can command each ignition coil ON/OFF by grounding the control circuit of the ignition coil. The control circuits are pulse width modulated (PWM) in order to precisely control the spark events.