DTC P0380 Federal
Circuit Description
The glow plug system is used to assist in providing the heat required to begin combustion during cold engine temperatures. The glow plugs are heated before and during cranking, as well as initial engine operation. The powertrain control module (PCM) controls the glow plug ON times by monitoring coolant temperature and glow plug voltage.
Conditions for Running the DTC
The ignition is in the ON position.
Conditions for Setting the DTC
| • | The PCM has commanded glow plugs ON and the glow plug signal voltage is less than 4 volts. |
| or |
| • | The PCM has commanded glow plugs OFF and the glow plug signal voltage is greater than 4 volts. |
| or |
| • | When the PCM has commanded the glow plugs ON and there is more than a 2-volt difference between glow plug voltage and ignition voltage. |
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. |
Diagnostic Aids
If the glow plug relay is stuck in the ON position, check for proper operation of the glow plugs, refer to Glow Plug System Diagnosis . When glow plugs are commanded ON by the scan tool, an internal PCM timer protects the glow plugs from damage by cycling them ON for 3 seconds and then OFF for 12 seconds.
The glow plug output feed wire nut and battery feed wire nut at the relay should be checked for proper torque, 5 N·m (44 lb in) and for corrosion.
An intermittent may be caused by the following conditions:
| • | Poor connections |
| • | Rubbed through wire insulation |
| • | Broken wire inside the insulation |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step will determine if DTC P0380 is a hard failure.
-
This step will determine if the PCM is requesting the glow plug system ON.
-
This step will determine if the glow plug relay has been activated and the output voltage has been seen by the PCM.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | ||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |
Does the scan tool display the Glow Plug System as enabled? | -- | Go to Step 3 | Go to Step 8 | |
Does the scan tool display the Glow Plugs at the specified value? | B+ | Go to Step 4 | Go to Step 6 | |
4 | Does the scan tool display Glow Plug voltage present all the time? | -- | Go to Step 17 | Go to Step 5 |
5 | The DTC is intermittent. If no additional DTCs are stored, refer to Diagnostic Aids. If any additional DTCs were stored, refer to those tables. Were there any additional DTCs stored? | -- | Go to Diagnostic Aids | |
6 |
Does the test lamp illuminate? | -- | Go to Step 7 | Go to Step 11 |
7 |
Does the test lamp illuminate? | -- | Go to Step 8 | Go to Step 12 |
8 |
Does the voltage measure at the specified value? | B+ | Go to Step 9 | Go to Step 13 |
9 |
Does the test lamp illuminate? | -- | Go to Step 10 | Go to Step 20 |
Does the test lamp illuminate when the scan tool commands the glow plugs ON? | -- | Go to Step 15 | Go to Step 19 | |
11 | Repair an open or a short to ground in glow plug relay ignition 1 voltage circuit. Did you complete the repair? | -- | Go to Step 22 | -- |
12 | Repair any open or poor connections in the glow plug relay ground circuit. Did you complete the repair? | -- | Go to Step 22 | -- |
13 |
Did you find and correct the condition? | -- | Go to Step 22 | Go to Step 14 |
14 | Check the glow plug relay control circuit for a proper connection at the PCM and replace the terminal if necessary. Did you find and correct the condition? | -- | Go to Step 22 | Go to Step 21 |
15 |
Did you find and correct the condition? | -- | Go to Step 22 | Go to Step 16 |
16 | Check the glow plug relay control circuit for a proper connection at the PCM and replace the terminal if necessary. Did you find and correct the condition? | -- | Go to Step 22 | Go to Step 21 |
17 |
Does the test lamp illuminate all the time? | -- | Go to Step 18 | Go to Step 19 |
18 | Repair the short to voltage on the glow plug relay control circuit. Did you complete the repair? | -- | Go to Step 22 | -- |
19 | Replace the glow plug relay. Refer to Glow Plug Relay Replacement . Did you complete the replacement? | -- | Go to Step 22 | -- |
20 | Repair an open or a short to ground in the battery positive voltage circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 22 | -- |
21 | Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the replacement? | -- | Go to Step 22 | -- |
22 |
Does the DTC run and pass? | -- | Go to Step 23 | Go to Step 2 |
23 | With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK | |
