Circuit Description
WARNING: This page is about a different car, the 2004 GMC Safari and 2004 Chevrolet Astro. However, it is still accessible from the selected car via links, so may be relevant.
The enhanced ignition system uses the crankshaft position (CKP) sensor to provide a timing input to the control module. Ignition control (IC) spark timing for each cylinder is based on this input. The control module provides the ignition timing signal to the ignition control module (ICM) to control the ignition coil. Each timing pulse detected by the ICM allows the ICM to energize the ignition coil. A large secondary ignition voltage is induced in the secondary coil winding by the primary coil winding. This high voltage is switched to the correct spark plug by the distributor. If the powertrain control module (PCM) detects an unusually high or low voltage on the ignition signal circuit, DTC P0351 sets.