DTC P0351: Ignition Control Circuit: Description
WARNING: This page is about a different car, the 2001 GMC Savana, 2001 Chevrolet RV Cutaway, 2001 Chevrolet Cutaway, and 2001 Chevrolet Chevy Express. However, it is still accessible from the selected car via links, so may be relevant.
Enhanced ignition system uses Crankshaft Position (CKP) sensor to provide a timing input to Powertrain Control Module (PCM). Ignition Control (IC) spark timing for each cylinder is based on this input. PCM provides ignition timing signal to Ignition Control Module (ICM) to control ignition coil. Each timing pulse detected by ICM allows ICM to energize ignition coil. A large secondary ignition voltage is induced in secondary coil by primary coil. This high voltage is switched to correct spark plug by the distributor. DTC P0351 will set if PCM detects an unusually high or low voltage on ignition timing signal circuit.