P1648-GLOW PLUG MODULE INTERNAL FAULT
For a complete wiring diagram Refer to Section 8W
| Possible Causes |
| BATTERY SUPPLY CIRCUIT OPEN |
| GROUND CIRCUIT OPEN |
| INTERMITTENT CONDITION |
| GLOW PLUG CONTROL MODULE |
Diagnostic Test
1. CHECK FOR ACTIVE DTCNOTE: If the ECM detects and stores a DTC, the ECM also stores the engine/vehicle operating conditions under which the DTC was set. Some of these conditions are displayed on the scan tool at the same time the DTC is displayed.
NOTE: Before erasing stored DTCs, record these conditions. Attempting to duplicate these conditions may assist when checking for an active DTC.
Turn the ignition on.
With the scan tool, erase ECM DTCs.
Turn the ignition off for 10 seconds.
Turn the ignition on.
Monitor the scan tool for ECM DTCs.
Repeat this test several times.
Did this DTC set again?
Yes
- Go To2
No
- Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)
2. GROUND CIRCUIT OPEN
Turn the ignition off.
Disconnect the Glow Plug Control Module harness connector.
Using a 12-volt test light connected to 12-volts, check the Ground circuit at the Glow Plug Control Module harness connector.
Does the test light illuminate brightly?
Yes
- Go To3
No
- Repair the Glow Plug Control Module Ground circuit for an open.
- Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).
3. BATTERY SUPPLY CIRCUIT OPEN
Using a 12-volt test light connected to ground, check the Battery Supply circuit at the Glow Plug Control Module harness connector.
Does the test light illuminate brightly?
Yes
- Replace the Glow Plug Control Module.
- Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).
No
- Repair the Glow Plug Control Module Battery Supply circuit for an open.
- Perform the ECM Verification Test Ver. 1 (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).