DTC P0380 Federal RPO FE9, NG1
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 engine control module (ECM) controls the glow plug ON times by monitoring coolant temperature and glow plug voltage.
Conditions for Running the DTC
The ignition switch in the ON position.
Conditions for Setting the DTC
| • | The ECM has commanded glow plugs ON and the glow plug signal voltage is less than 4 volts. |
| or |
| • | The ECM has commanded glow plugs OFF and the glow plug signal voltage is more than 4 volts. |
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 ECM 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:
| • | 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 determines if there is a relay control circuit or ECM fault that will not energize the relay.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module Connector End Views or Engine Controls Connector End Views | ||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |
Confirm that the glow plugs are commanded OFF with the scan tool. Does the scan tool display glow plug feedback signal voltage present all the time? | -- | Go to Step 9 | Go to Step 3 | |
|
Important: The DMM may indicate a bias voltage on the circuit before the relay is energized. This is normal.
Does the voltage measure near the specified value when the relay is commanded ON? | B+ | Go to Step 4 | Go to Step 8 | |
4 |
Does the test lamp illuminate? | -- | Go to Step 5 | Go to Step 12 |
5 | Probe the ground circuit of the glow plug relay with a test lamp connected to battery voltage. Refer to Troubleshooting with a Test Lamp in Wiring Systems. Does the test lamp illuminate? | -- | Go to Step 6 | Go to Step 13 |
6 |
Does the test lamp illuminate when the scan tool commands the glow plugs ON? | -- | Go to Step 7 | Go to Step 17 |
7 |
Did you find a problem? | -- | Go to Step 14 | Go to Step 18 |
8 |
Did you find and correct the condition? | -- | Go to Step 21 | Go to Step 18 |
9 |
Does the test lamp illuminate all of the time? | -- | Go to Step 10 | Go to Step 11 |
10 |
Does the test lamp illuminate? | -- | Go to Step 16 | Go to Step 20 |
11 | Probe the glow plug signal circuit at the harness connector with a test lamp connected to a good ground. Refer to Troubleshooting with a Test Lamp in Wiring Systems. Does the test lamp illuminate? | -- | Go to Step 15 | Go to Step 19 |
12 | Repair the open or short to ground in the battery positive voltage circuit to the glow plug relay. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 21 | -- |
13 | Repair the open in the glow plug relay ground circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 21 | -- |
14 | Repair the open or short to ground in the glow plug signal circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 21 | -- |
15 | Repair the short to voltage in the glow plug signal circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 21 | -- |
16 | Repair the short to voltage in glow plug relay control circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 21 | -- |
17 |
Did you find and correct the condition? | -- | Go to Step 21 | Go to Step 19 |
18 |
Did you find and correct the condition? | -- | Go to Step 21 | Go to Step 20 |
19 | Replace the glow plug relay. Refer to Glow Plug Relay Replacement . Did you complete the replacement? | -- | Go to Step 21 | -- |
20 | Replace the ECM. Refer to Engine Control Module Replacement . Did you complete the replacement? | -- | Go to Step 21 | -- |
21 |
Does the DTC run and pass? | -- | Go to Step 22 | Go to Step 1 |
22 | With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK | |
DTC P0380 California RPO YF5, NE1, NF4, VCL
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 engine control module (ECM) controls the glow plug ON times by monitoring coolant temperature and glow plug voltage. The California Glow Plug system has eight individual glow plug supply circuits between the controller and the glow plugs. If the feedback voltage from the controller to the ECM is not within range, DTC P0380 will set.
Conditions for Running the DTC
The ignition is ON.
Conditions for Setting the DTC
| • | The glow plugs are commanded OFF and the glow plug feedback is more than 2 volts. |
| or |
| • | The glow plugs are commanded on and the glow plug feedback is not between 5 volts and 6.2 volts. |
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
Important: If the glow plug relay is stuck in the ON position, check for proper operation of the glow plugs. When the glow plugs are commanded ON by the scan tool, an internal engine control module (ECM) timer protects the glow plugs from damage by cycling them ON for 3 seconds and the OFF for 12 seconds. The glow plug relay battery feed wire nut at the relay should be tested for proper torque. The California glow plug system will send the following voltages, or signals to the ECM:
Signal Voltage | Glow Plugs Failed Open |
|---|---|
5.00-6.00 | None |
2.00-3.00 | 1 |
1.00-2.00 | 2 |
0.80-1.70 | 3 |
Less than 1.3 | 4 or more |
An intermittent may be caused by the following:
| • | Poor connections, terminal tension |
| • | Rubbed-through wire insulation |
| • | Broken wire inside the insulation |
| • | A short to battery positive voltage on the glow plug relay control circuit |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
All 4 DTCs must be set to answer yes.
-
This step will determine if DTC P0380 is a hard failure.
-
This step will determine if there is a short to voltage on the signal circuit.
-
This step will determine if there is ignition voltage at the glow plug relay.
-
This step will determine if the glow plug control circuit and ECM are working properly.
-
This step will determine if there is a short to voltage on the relay control circuit.
-
This step will determine if the glow plugs or the glow plug harness is causing the DTC P0380.
Step | Action | Values | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | -- | ||||||
2 |
Important : If this DTC set after an ECM reflash.
Does the scan tool display the Glow Plug System Type as California? | -- | Go to Step 3 | Go to DTC P0380 | ||||||
Did DTC P0489, P0540, P2141, and P2144 also set? | -- | Go to Step 16 | Go to Step 4 | |||||||
Does the scan tool display the glow plug feedback parameter is within the specified range? | 5.0-5.6 V | Go to Step 8 | Go to Step 5 | |||||||
Does the scan tool display a glow plug voltage more than the specified value? | 5.6 V | Go to Step 22 | Go to Step 6 | |||||||
6 | Does the scan tool display a glow plug voltage more than the specified value? | 0.70 V | Go to Step 11 | Go to Step 7 | ||||||
7 |
Does the test lamp illuminate? | -- | Go to Step 9 | Go to Step 25 | ||||||
8 | 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 | |||||||
Does the test lamp illuminate? | -- | Go to Step 10 | Go to Step 17 | |||||||
10 |
Does the test lamp illuminate? | -- | Go to Step 11 | Go to Step 18 | ||||||
Does the test lamp illuminate with the scan tool command ON? | -- | Go to Step 13 | Go to Step 12 | |||||||
Does the test lamp illuminate all of the time? | -- | Go to Step 24 | Go to Step 19 | |||||||
13 |
Does the glow plug parameter voltage measure near the specified value? | Battery Voltage | Go to Step 14 | Go to Step 21 | ||||||
Is the resistance within the specified range for each circuit, and consistent across all circuits? | 2-4Ω | Go to Step 27 | Go to Step 15 | |||||||
15 |
Is the resistance within the specified range? | 2-4Ω | Go to Step 27 | Go to Step 26 | ||||||
16 | Repair the open or short to ground between the fuel heater fuse and the supplied components. Did you complete the repair? | -- | Go to Step 30 | -- | ||||||
17 | Repair an open in the glow plug relay ignition 1 voltage circuit. Did you complete the repair? | -- | Go to Step 30 | -- | ||||||
18 | Repair the open circuit or poor connections in the glow plug relay harness ground circuit. Did you complete the repair? | -- | Go to Step 30 | -- | ||||||
19 | Inspect the glow plug relay control circuit for an open or short to ground and repair as necessary. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 30 | Go to Step 20 | ||||||
20 | Inspect the glow plug relay control circuit for a proper connection at the ECM and replace the terminal if necessary. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 30 | Go to Step 29 | ||||||
21 | Inspect the glow plug relay signal circuit for an open or short to ground and repair as necessary. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 30 | Go to Step 28 | ||||||
22 | Inspect the glow plug relay signal circuit for a proper connection at the ECM and replace the terminal if necessary. Did you find an improper connection and make the necessary replacement? | -- | Go to Step 30 | Go to Step 23 | ||||||
23 | Inspect for a short to voltage in the glow plug relay signal circuit and repair as necessary. Refer to Wiring Repairs in Wiring Systems. Did you find the improper condition? | -- | Go to Step 30 | Go to Step 27 | ||||||
24 | Inspect for a short to voltage in the glow plug control circuit and repair as necessary. Refer to Wiring Repairs in Wiring Systems. Did you find the improper condition? | -- | Go to Step 30 | Go to Step 29 | ||||||
25 | Repair the open or poor connection on the battery voltage circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 30 | -- | ||||||
26 | Replace any glow plug that had resistance outside the specified range. Did you complete the replacement? | -- | Go to Step 30 | -- | ||||||
27 | Inspect for the following conditions:
Did you find and correction the condition? | -- | Go to Step 30 | Go to Step 28 | ||||||
28 | Replace the glow plug relay. Refer to Glow Plug Relay Replacement. Did you complete the replacement? | -- | Go to Step 30 | -- | ||||||
29 | Replace the ECM. Refer to Engine Control Module Replacement. Did you complete the replacement? | -- | Go to Step 30 | -- | ||||||
30 |
Does the DTC run and pass? | -- | Go to Step 31 | Go to Step 1 | ||||||
31 | With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK |
