P1648-GLOW PLUG MODULE INTERNAL

For a complete wiring diagram Refer to Section 8W

When Monitored:
With the ignition on.
Set Condition:
The Glow Plug Control Module reports an internal fault to the ECM.

Possible Causes

INTERMITTENT DTC

GLOW PLUG MODULE

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)

Diagnostic Test

1. DTC IS ACTIVE

Ignition on, engine not running.
With the scan tool, Clear DTCs.
Monitor the scan tool for at least two minutes.
Cycle the ignition key off and on several times, leaving the ignition on for at least 10 seconds at a time.
Start the engine.
Allow the engine to reach normal operating temperature.
With the scan tool, select View DTCs.

Is the status Active for this DTC?

Yes

Go To 2

No

Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)

2. GLOW PLUG MODULE

Using the wiring diagram/schematic as a guide, inspect the Glow Plug Module wiring and connectors.
Look for any chafed, pierced, pinched, or partially broken wires.
Look for broken, bent, pushed out or corroded terminals.
Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.
Look for the data to change or for the DTC to reset during the wiggle test.
Refer to any Technical Service Bulletins that may apply.

Were any problems found?

Yes

Repair as necessary.

Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

No

Replace the Glow Plug Module in accordance with the Service Information.
Perform the ECM Verification Test Ver. 1. (Refer to 9 - ENGINE - STANDARD PROCEDURE)