Symptom:
*CHECKING THE FUEL COMPUTER
POSSIBLE CAUSES
ECM - FUEL COMPUTER OUTPUT CIRCUIT
FUEL COMP OUPUT CIRCUIT SHORTED TO VOLTAGE
FUEL COMPUTER OUTPUT CIRCUIT OPEN
FUEL COMPUTER OUTPUT CIRCUIT SHORT TO GROUND
OVERHEAD CONSOLE
PCM
PCM - FUEL COMPUTER OUTPUT CIRCUIT
TEST
ACTION
APPLICABILITY
1
Turn the ignition off.
Disconnect the ECM harness connectors.
Turn the ignition on.
Measure the voltage of the Fuel Computer Output circuit at the ECM harness
connector.
Is the voltage between 4.5 and 5.5 volts?
All
Yes
→
Go To
2
Below 4.5 volts
Go To
4
Above 5.5 volts
Repair the Fuel Computer Output circuit for a short to voltage.
Perform ROAD TEST VERIFICATION - VER-2.
2
Turn the ignition off.
Disconnect the ECM harness connectors.
Turn the ignition on.
Connect a jumper wire between ground and ECM harness connector C1 cavity 18
while observing the Overhead Fuel Computer.
Did the Overhead Fuel Computer status change?
All
Yes
→
Replace the ECM in accordance with the Service Information.
Perform ROAD TEST VERIFICATION - VER-2.
No
→
Go To
3
3
Turn the ignition off.
Disconnect the ECM harness connectors.
Turn the ignition on.
Connect one end of a jumper wire to ECM harness connector C1 cavity 18 while
observing the Overhead Fuel Computer.
With the DRB, select Body System and monitor PCI Bus Info while connecting and
disconnecting the other end of the jumper wire to ground.
Does the DRB display a change in Fuel Computer Status?
All
Yes
→
Replace the Overhead Console in accordance with the Service
Information.
Perform ROAD TEST VERIFICATION - VER-2.
No
→
Test Complete.
244
DRIVEABILITY - DIESEL