P067A-CYLINDER 4 GLOW PLUG CIRCUIT LOW
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For a complete wiring diagram, refer to the Wiring Information.
Theory of Operation
The Glow Plug Module has the appearance of a large relay and is located next to the battery. The Glow Plug Module receives a signal from the Powertrain Control Module (PCM) to activate the Glow Plugs. The Glow Plug Module supplies power to the Glow Plugs and a ground path is provided through the body of the Glow Plugs. The Glow Plug Module communicates with the PCM over the (K330) Glow Plug Module Control circuit.
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When Monitored:
Continuously with the ignition on and the Glow Plugs commanded on.
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Set Condition:
The PCM detects a short circuit on the Cylinder 4 Glow Plug circuit.
Possible Causes |
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| (A208) GLOW PLUG 4 CONTROL CIRCUIT SHORTED TO GROUND |
| (A208) GLOW PLUG 4 CONTROL CIRCUIT SHORTED TO VOLTAGE |
| GLOW PLUG 4 |
| GLOW PLUG MODULE |
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).
| 1. | Ignition on, engine not running. |
| 2. | With the scan tool, erase DTCs in the PCM. |
| 3. | Perform several ignition cycles leaving the ignition on for at least 10 seconds then off for 10 seconds. |
| 4. | With the scan tool, read the PCM DTCs. |
Did this DTC return?
Yes
- Go To 2
No
- Perform the INTERMITTENT DTC diagnostic procedure. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).
2. CHECK THE (A208) GLOW PLUG 4 CONTROL CIRCUIT FOR A SHORT TO GROUND
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| 1. | Turn the ignition off. |
| 2. | Disconnect the Glow Plug 4 harness connector. |
| 3. | Disconnect the Glow Plug Module harness connector. |
| 4. | Measure the resistance between ground and the (A208) Glow Plug 4 Control circuit at the Glow Plug 4 harness connector. |
Is the resistance below 10k Ohms?
Yes
- Repair the (A208) Glow Plug 4 Control circuit for a short to ground.
- Perform the PCM VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).
No
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Go To 3
3. CHECK THE (A208) GLOW PLUG 4 CONTROL CIRCUIT FOR A SHORT TO VOLTAGE
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| 1. | Turn the ignition on. |
| 2. | Measure the voltage of the (A208) Glow Plug 4 Control circuit at the Glow Plug 4 harness connector. |
Is there voltage present on the (A208) Glow Plug 4 Control circuit?
Yes
- Repair the (A208) Glow Plug 4 Control circuit for a short to voltage.
- Perform the PCM VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).
No
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Go To 4
| 1. | Turn the ignition off. |
| 2. | Replace Glow Plug 4 in accordance with the service information. |
| 3. | Turn the ignition on. |
| 4. | With the scan tool, erase PCM DTCs. |
| 5. | Perform several ignition key cycles leaving the ignition on for at least 10 seconds per cycle. |
| 6. | With the scan tool, read PCM DTCs. |
Does the scan tool display this DTC?
Yes
- Go To 5
No
- Test complete.
- Perform the PCM VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).
| 1. | Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Glow Plugs and the Glow Plug Module. |
| 2. | Look for any chafed, pierced, pinched, or partially broken wires. |
| 3. | Look for broken, bent, pushed out or corroded terminals. |
| 4. | Perform any Technical Service Bulletins that may apply. |
Were any problems found?
Yes
- Repair as necessary.
- Perform the PCM VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).
No
- Replace the Glow Plug Module in accordance with the Service Information.
- Perform the PCM VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).