
(Table 69, contd)
Troubleshooting Test Steps
Values
Results
3. Check the Glow Plug for the Suspect Cylinder
A. Turn the keyswitch to the OFF position.
B. Disconnect the connectors for the glow plugs in any sus-
pect cylinders. Refer to Table 68 in order to identify which cyl-
inders are suspect.
C. Use a multimeter to measure the resistance between the
suspect glow plug connector and a suitable engine ground.
Resistance
Result:
The measurement indicates an open circuit between
the glow plug and the ground point.
The glow plug is faulty.
Replace the suspect glow plug. Refer to Disassembly and As-
sembly, “Glow Plugs - Remove and Install”.
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 measurement indicates that there is a resistance
between the glow plug and the ground point.
The glow plug is OK.
Proceed to Test Step 4.
4. Check the Glow Plug Wiring for an Open Circuit
A. Turn the keyswitch to the OFF position.
B. Disconnect the connectors for any suspect glow plugs. Dis-
connect the connector for the GCU.
C. Use a multimeter to measure the resistance between the
harness connector for the suspect glow plug and the appropri-
ate terminal on the GCU connector.
Less than 5
Ohms
Result:
At least one of the resistance measurements is greater
than 5 Ohms.
The fault is in the wiring between the suspect glow plug and the
GCU.
Check all wiring between the suspect glow plug and the GCU.
Refer to the Electrical Schematic for the application.
Make any necessary repairs.
Result:
All resistance measurements are less than 5 Ohms.
Reconnect all connectors. Proceed to Test Step 5.
5. Check the Glow Plug Wiring for a Short Circuit
A. Turn the keyswitch to the OFF position.
B. Disconnect the connector for the suspect glow plug.
C. Use a multimeter to measure the resistance between the
harness connector for the suspect glow plug and engine
ground.
Greater than 1 k
Ohm
Result:
The measured resistance is less than 1 k Ohm.
There is a short to ground in the wiring for the suspect glow
plug.
Check the wiring between the suspect glow plug and the GCU.
Refer to the Electrical Schematic for the application.
Make any necessary repairs.
Result:
The measured resistance is greater than 1 k Ohm.
The wiring is OK.
Install a replacement GCU.
Use the electronic service tool to override the glow plug start
aid and verify that the repair eliminates the fault.
(continued)
134
UENR0612
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