PFI Chart C-1, Pcm Replacement Check
Before replacing PCM, ensure connector contact circuits are functional, and there are no shorts from battery voltage to ground on any PCM circuits. Check IGN fuse in fuse block.
NOTE:
Test numbers refer to test numbers on diagnostic chart.
- PCM supplies power through a high side driver to cruise control vent and vacuum solenoids. An internal short in servo causing a low resistance or short in wiring harness may damage PCM or cause servo solenoid failure.
- PCM supplies power to fuel pump relay through high side driver. An internal short in relay winding causing low resistance or short in wiring harness may cause PCM damage or relay failure.
- PCM supplies power to ISC through an internal switching IC changes circuit polarity. An internal short in ISC motor windings or short in wiring harness may cause PCM damage or ISC motor failure.
- PCM provides ground EGR solenoid, Electric Switching Valve (ESV), canister purge solenoid and Electric Divert Valve (EDV) through a quad driver IC. An internal short in windings or resistor of devices or short in wiring harness may cause damage to PCM or Emission Control System (ECS) device.
- PCM provides ground VCC solenoid in transmission through a quad driver IC. An internal short in winding or diode of solenoid or short in wiring harness may cause PCM damage or solenoid failure.