Allante V8-273 4.5L (1991)
Connector And Fuse Block.
DESCRIPTION:
Prior to replacing an ECM, the vehicle must be tested for:
1.
Check connector terminals that they are properly seated and locked in the connector and terminal retainers are properly positioned and locked.
2.
Check PCM ground at the generator and battery ground at the engine and chassis.
3.
Check Ignition 1-ISO fuse in the fuse block.
NOTES ON FAULT TREE:
1.
The PCM supplies power through a high side driver to the cruise control vent and vacuum solenoids. An internal short in the servo causing a low
resistance or short to ground in the wiring harness may damage the PCM or cause the servo or solenoids to fail.
2.
The PCM supplies power to the fuel pump relay through a high side driver. An internal short in the relay winding causing a low resistance or short
to ground in the wiring harness may cause damage to the PCM or the relay to fail.
3.
The PCM supplies power to the ISC through an internal switching IC that will change polarity of the circuit. An internal short in the ISC motor
armature windings or short to ground in the wiring harness may cause damage to the PCM or the ISC motor to fail.
4.
The PCM provides the ground for the EGR solenoid, Electric Switching Valve (ESV), Canister Purge solenoid, and Electric Divert Valve (EDV)
through a quad driver IC. An internal short in the windings or resistor of the devices or a short to ground in the wiring harness may cause damage
to the PCM or the Emission Control System (ECS) device.
5.
The PCM provides the ground for the VCC solenoid in the transmission through a quad driver IC. An internal short in the winding or diode of the
solenoid or a short to ground in the wiring harness may cause damage to PCM or the solenoid to fail.
