(Table 69, contd)
Troubleshooting Test Steps
Values
Results
6. Check that the GCU is Receiving the Correct Voltage
A. Turn the keyswitch to the OFF position.
B. Disconnect the GCU.
C. Turn the keyswitch to the ONposition.
D. Measure the voltage between pin 4 on the harness connec-
tor for the GCU and a suitable ground.
10 V to 14 V
Result:
The measured voltage is not within the expected
range.
Check the fuse for the GCU. If the fuse is blown, replace the
fuse.
If the fuse is replaced and the fault reoccurs, there is a short in
the wiring between the battery supply and pin 4 on the GCU.
If the fuse is not blown, there is an open circuit in the wiring be-
tween the battery supply and pin 4 on the GCU.
Repair the faulty wiring or replace the faulty wiring. Reconnect
the GCU. Use the electronic service tool to override the glow
plug start aid and verify that the repair eliminates the fault.
Clear all logged diagnostic codes.
Result:
The measured voltage is within the expected range.
Proceed to Test Step 7.
7. Check That the GCU is Grounded Correctly
A. Turn the keyswitch to the OFF position.
B. Disconnect the GCU.
C. Turn the keyswitch to the ON position.
D. Measure the voltage between pin 4 and pin 5 on the har-
ness connector for the GCU.
10 V to 14 V
Result:
The measured voltage is not within the expected
range.
The fault is in the wiring between pin 5 on the harness connec-
tor for the GCU and P1:41.
Inspect the 9-pin engine interface connector. Repair the faulty
wiring or replace the faulty wiring. Use the electronic service
tool to override the glow plug start aid and verify that the repair
eliminates the fault.
Clear all logged diagnostic codes.
Result:
The measured voltage is within the expected range.
Proceed to Test Step 8.
8. Check the Type of Active Diagnostic Code
A. Turn the keyswitch to the ON position.
B. Use the electronic service tool to override the glow plug
starting aid.
C. Check for active diagnostic codes.
D. Use the electronic service tool to turn off the glow plug start-
ing aid.
E. Turn the keyswitch to the OFF position.
Diagnostic
Codes
Result:
A 676-5 diagnostic code is active
Proceed to Test Step 9.
Result:
A 676-6 diagnostic code is active
Proceed to Test Step 11.
Result:
A 676-19 diagnostic code is active
Proceed to Test Step 13.
(continued)
UENR0612
135
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