With Vehicle Control Module (VCM-A)

Service of the Vehicle Control Module (VCM-A) consists of replacement of VCM-A. If the diagnostics call for replacement of the VCM-A, it will be necessary to transfer the Knock Sensor (KS) Calibration Programmable Read Only Memory (PROM) and program the Electrically Erasable Programmable Read Only Memory (EEPROM) in the VCM-A using the procedure under EEPROM Programming. Testing and Inspection


NOTE: When replacing the production VCM-A with a service VCM-A (controller), it is important to transfer the broadcast code and production VCM-A number to the service VCM-A label. This will allow positive identification of VCM-A parts throughout the service life of the vehicle. Also transfer the KS Calibration PROM.

KS Calibration PROM
Refer to Knock Sensor (KS) Module for removal and installation of the KS Calibration PROM. Service and Repair

NOTE: To prevent internal VCM-A damage, the ignition must be "OFF,' when disconnecting or reconnecting power to the VCM-A (for example, battery cable, Engine Control Module (ECM) fuse, jumper cables, etc.).

CAUTION: To prevent possible Electrostatic Discharge damage to the VCM-A, Do Not touch the connector pins or soldered components on the circuit board.

Central MFI Assembly Parts Identification:

REMOVE OR DISCONNECT
1. Negative battery cable.
2. Plastic cover.
3. Wire harnesses, including:

^ Throttle Position (TP) sensor.
^ Idle Air Control (IAC) motor.
^ Manifold Absolute Pressure (MAP) sensor.
^ Intake manifold tuning valve assembly.

4. Throttle and cruise cable from upper intake manifold.
5. Ignition coil.
6. Crankcase ventilation hose at upper intake manifold.
7. Vacuum hoses at front and rear of upper intake manifold.
8. Air cleaner snorkel.
9. Upper intake manifold bolts and studs.

^ Mark the location of all studs for proper reassembly.

10. Upper intake manifold.

NOTE: Do Not attempt to disassemble the Central MFI assembly, it is serviceable as an assembly.

CAUTION: Refer to Fuel Pressure Relief Procedure before disconnecting fuel lines. Service and Repair

REMOVE OR DISCONNECT
1. Remove injector wiring harness connector at Central MFI assembly.
2. Fuel fitting clip and discard.
3. Fuel inlet and return tube and fitting assembly.

^ Discard 0-ring seals.

4. Central MFI assembly.

^ Squeeze poppet nozzle locking tabs together while lifting nozzle out of casting socket.
^ After removing the six poppet nozzles, lift the Central MFI assembly out of casting.

INSTALL OR CONNECT

WARNING: To reduce the risk of fire and personal injury, verify that the poppet nozzles are firmly seated and locked in their casting sockets. An unlocked poppet nozzle could work loose from its socket thus resulting in a fuel leak.

1. Central MFI assembly.

^ Align Central MFI assembly grommet with the casting grommet slots and push down until it is seated in bottom guide hole.
^ Push poppet nozzles into casting sockets.

INSPECT
^ Poppet nozzles must be firmly seated and locked in casting sockets. Refer to "CAUTION" statement above.

2. Fuel inlet and return tube and fitting assembly.

^ New 0-ring seals coated with clean engine oil.

3. New fuel fitting clip.

NOTE: Test for fuel leakage. Pressurize fuel system, verify no fuel leakage at inlet and return tube to Central MFI unit.