Glow Plug Monitor Self-Test
The Glow Plug Monitor self-test is a functional KOER self-test of the glow plug system. The PCM activates the GPCM, which monitors the glow plugs. A fault must be present at the time of testing to detect a fault. If the GPCM detects a fault, a message is sent to the PCM through the diagnostic line and then transmitted to the diagnostic tool.
NOTE:
The accelerator pedal may be used to increase the engine RPM and maintain battery voltage during the self-test. Make sure that the vehicle batteries are fully charged prior to carrying out the Glow Plug Monitor self-test.
CAUTION:
GPCM connectors are not interchangeable. The system generates DTCs if the connectors are mismatched. Make sure the green harness connector is plugged into the green module connector and the black harness connector into the black module connector. There is a black stripe on the GPCM housing for visual verification. The stripe should line up with the black connector.
CAUTION:
When disconnecting the green and black connectors at the GPCM it is suggested that the module be unbolted from the mounting bracket first and then the connectors disconnected. This allows for easier disconnect and prevents damage to the connector terminals.
CAUTION:
The PCM harness connectors must be properly seated and the connector latch properly attached to eliminate possible driveability concerns or a no start condition. Installing the PCM connectors on an angle may cause an improper connection, misdiagnosis, and damaged components. Install the connector until the lever pivots and seats itself. Apply light pressure to get the connector into position on the PCM and then fully seat the connector.
NOTE:
Visually inspect the harness connectors for corrosion, damage, proper mating, and correct pin tension.
This pinpoint test is intended to diagnose the following:
- glow plugs
- glow plug bus bar
- GPCM
- PCM
GPCM PIN NUMBER/SIGNAL NAME
| GPCM Pin Number | Signal Name | |
|---|---|---|
| GREEN Connector | BLACK Connector | |
| 1 | Glow Plug Number 5 | Glow Plug Number 6 |
| 2 | Glow Plug Number 7 | Glow Plug Number 8 |
| 3 | VBATT, Glow Plug Power | VBATT, Glow Plug Power |
| 6 | Glow Plug Number 1 | Glow Plug Number 2 |
| 7 | Glow Plug Number 3 | Glow Plug Number 4 |
| 8 | Glow Plug Control | Not Connected |
| 9 | Diagnostic Communication | VPWR, GPCM Power |