Circuit Description
The glow plug controller has the ability to perform internal diagnostics for voltage and output state of the glow plugs. If the glow plug controller senses an open in the main battery supply to the glow plug controller, or a condition with any of the glow plug driver circuits, the glow plug controller will send an error message to the engine control module (ECM).
DTC Descriptor
This diagnostic supports the following DTC:
DTC P0670 Glow Plug Module Control Circuit
Conditions for Running the DTC
| • | DTC U0073 or U0106 is not set. |
| • | The ignition is ON. |
Conditions for Setting the DTC
The glow plug controller detects an open to the main battery supply for the glow plugs, or an open in all 8 glow plug circuits.
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
| • | Clear the MIL and the DTC with a scan tool. |
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | ||||
1 | Did you perform the Diagnostic System Check - Engine Controls? | -- | Go to Step 2 | |
2 |
Did the DTC fail this ignition? | -- | Go to Step 3 | Go to Intermittent Conditions |
3 | Is DTC P0671-P0678 set? | -- | Go to Step 4 | Go to Step 5 |
4 |
Important: The DMM and test leads must be calibrated to 0 ohms in order to prevent misdiagnosis. Use the DMM to perform this test. Refer to the DMM User Manual for calibration procedure.
Does the DMM display a resistance below the specified value? | 1 ohms | Go to Step 6 | Go to Step 7 |
5 |
Does the test lamp illuminate? | -- | Go to Step 6 | Go to Step 8 |
6 | Test for an intermittent and for a poor connection at the harness connector of the glow plug controller. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 11 | Go to Step 10 |
7 | Repair the ground circuit of the glow plug harness between the glow plug controller and the engine ground for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 9 | -- |
8 | Repair the openor short to ground in the pattery positive voltage circuit between the glow plug controller and the battery. Did you complete the repair? | -- | Go to Step 11 | -- |
9 | Replace the glow plugs. Refer to Glow Plug Replacement - Bank 1 and Glow Plug Replacement - Bank 2 . Did you complete the replacement? | -- | Go to Step 11 | -- |
10 | Replace the glow plug controller. Refer to Glow Plug Controller Replacement . Did you complete the replacement? | -- | Go to Step 11 | -- |
11 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 12 |
12 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | System OK | |
