Circuit Description

The powertrain control module (PCM)/engine control module (ECM) provides a ground for electronic spark timing B circuit. When PCM/ECM removes ground path of ignition primary coil, magnetic field produced by coil collapses. The collapsing magnetic field produces a voltage in secondary coil which fires spark plug. The circuit between PCM/ECM and electronic ignition system is monitored for an open circuit, short to voltage, and short to ground. When PCM/ECM detects a problem in spark timing B circuit, it will set DTC P0351.