DTC P0380 Glow Plug Feedback Circuit Federal
Refer to
Cell 22: Underhood Bussed Electrical Center, G104, Instrument Cluster
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 PCM controls the glow plug ON times by monitoring coolant temperatures and glow plug voltage.
Conditions for Running the DTC
The PCM has commanded glow plugs ON.
or
The PCM has commanded glow plugs OFF.
or
When the PCM has commanded glow plugs ON.
Conditions for Setting the DTC
| • | The glow plug signal voltage is less than 4.0 volts. |
| or |
| • | The glow plug signal voltage is greater than 4.0 volts. |
| or |
| • | There is more than a 2 volt difference between glow plug voltage and ignition voltage. |
Action Taken When the DTC Sets
| • | The PCM illuminates the malfunction indicator lamp (MIL) on the first consecutive drive trip that the diagnostic runs and fails. |
| • | The Freeze Frame records the operating conditions at the time of failure and updates the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn the MIL off after three consecutive trips without a fault condition. |
| • | A History DTC will clear after forty consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures. |
| • | Use of a scan tool. |
Diagnostic Aids
If glow plug relay is stuck in the ON position, check for proper operation of glow plugs, refer to Glow Plug System Check . 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 the 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 number(s) below refer to the Step number(s) on the Diagnostic Table.
-
This Step will determine if P0380 is a hard failure.
-
This Step will determine if the PCM is requesting the glow plug system is 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 | Value(s) | Yes | No |
|---|---|---|---|---|
1 |
Important: Before clearing any DTCs, use the scan tool Capture Info to save the Freeze Frame and Failure Records for reference. The control module's data is deleted once the Clear Info function is used. Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||
Does the scan tool display the Glow Plug System as enabled? | -- | |||
Does the scan tool display the Glow Plugs at the specified value? | B+ | |||
4 | Does the scan tool display Glow Plug voltage present all the time? | -- | ||
5 | The DTC is intermittent. If no additional DTCs are stored, refer to Diagnostic Aids If any additional DTCs were stored, refer to those table(s). Were there any additional DTCs stored? | -- | Go to the applicable DTC table | Go to Diagnostic Aids |
6 |
Is the test light ON? | -- | ||
7 |
Is the test light ON? | -- | ||
Is the voltage at the specified value? | B+ | |||
9 |
Is the test light ON when the scan tool commands the glow plugs ON? | -- | ||
10 | Repair an open or a short to ground in glow plug relay ignition feed circuit. Is the action complete? | -- | -- | |
11 | Repair any open or poor connections in the glow plug relay ground circuit. Is the action complete? | -- | -- | |
12 |
Did you perform a repair? | -- | ||
13 | Check the glow plug relay control circuit for a proper connection at the PCM and replace the terminal if necessary. Did you perform a repair? | -- | ||
14 |
Did you perform a repair? | -- | ||
15 | Check the glow plug relay signal circuit for a proper connection at the PCM and replace the terminal if necessary. Did you peform a repair? | -- | ||
16 |
Is the test light ON all the time? | -- | ||
17 | Repair the short to voltage on the glow plug relay control circuit. Is the action complete? | -- | -- | |
18 | Replace the glow plug relay. Is the action complete? | -- | -- | |
19 |
Important: The new PCM must be programmed. Replace the PCM. Is the action complete? | -- | -- | |
20 |
Does the scan tool indicate the diagnostic Passed? | -- | ||
21 | Does the scan tool display any additional undiagnosed DTCs? | -- | Go to the applicable DTC table | System OK |
DTC P0380 Glow Plug Feedback Circuit California
Refer to
Cell 22: Underhood Bussed Electrical Center, G104, Instrument Cluster
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 PCM controls the glow plug ON times by monitoring coolant temperatures and glow plug voltage. The PCM performs this diagnostic continuously.
The California type glow plug system has the ability to detect if one or more glow plugs have failed or a glow plug relay failure. The California type glow plug system detects a failure by sending a signature voltage to the PCM. This signal is not based on system voltage.
Conditions for Running the DTC
The ignition switch 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 5.0 volts. |
| or |
| • | The PCM has commanded glow plugs ON and the glow plug signal voltage is greater than 6.2 volts. |
| or |
| • | The PCM has commanded glow plugs OFF and the glow plug signal voltage is greater than 2.0 volts. |
Action Taken When the DTC Sets
| • | The PCM illuminates the malfunction indicator lamp (MIL) on the second consecutive drive trip that the diagnostic runs and fails. |
| • | The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the Failure Records will store this information. If the diagnostic reports a failure on the second consecutive drive trip, the Freeze Frame records the operating conditions at the time of failure and updates the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn the MIL off after three consecutive trips without a fault condition. |
| • | A History DTC clears after forty consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures. |
| • | The use of a Scan Tool |
Diagnostic Aids
Important: Remove any debris from the PCM module connector surfaces before servicing the PCM module. Inspect the PCM module connector gaskets when diagnosing/replacing the module. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion into the PCM module.
If a P0380 DTC sets after the PCM has been flashed, the glow plug system must be relearned. Refer to Glow Plug System Type Relearn .If glow plug relay is stuck in the ON position, check for proper operation of glow plugs. 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 the OFF for 12 seconds.
The glow plug relay battery feed wire nut at the relay should be checked for proper torque .
The California glow plug system will send the following voltages (signal) to the PCM.
Signal Voltage | Glow Plugs |
|---|---|
5.62 - 6.02 | None |
2.82 - 3.09 | 1 |
1.88 - 2.07 | 2 |
1.42 - 1.56 | 3 |
Less than 1.25 | 4 or more |
An intermittent may be caused by the following:
| • | Poor connections (terminal tension). |
| • | Rubbed through wire insulation. |
| • | Broken wire inside the insulation. |
Test Description
The number(s) below refer to the Step number(s) on the Diagnostic Table.
-
This step will determine if 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 igniton voltage at the glow plug relay.
-
This step will determine if the glow plug control circuit and PCM 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 P0380.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 |
Important: Before clearing any DTCs, use the scan tool Capture Info to save the Freeze Frame and Failure Records for reference. The control module's data is deleted once the Clear Info function is used. Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||
2 |
Important: If this DTC set after a PCM reflash. Does the scan tool display the Glow Plug System Type as California? | -- | ||
Does the scan tool display the Glow Plugs parameter equal to or between the specified value? | 6.2 - 5.0 V | |||
Does the scan tool display a glow plug voltage greater than the specified value? | 6.2 V | |||
5 | Does the scan tool display glow plug voltage greater than the specified value? | 2.0 V | ||
6 |
Is the test light ON? | -- | ||
7 | The DTC is intermittent. If no additional DTCs are stored, refer to Diagnostic Aids If any additional DTCs were stored, refer to those table(s). Were there any additional DTCs stored? | -- | Go to the applicable DTC table | Go to Diagnostic Aids |
Is the test light ON? | -- | |||
9 |
Is the test light ON? | -- | ||
10 |
Does the test light follow the scan tool commands? | -- | ||
11 | Is the test light on all the time? | -- | ||
12 |
Is the voltage at the specified value? | 6.2 - 5.0 V | ||
Does each circuit turn ON the test light? | -- | |||
14 |
Does each glow plug illuminate the test light? | -- | ||
15 |
Is the test light OFF at each of the circuits? | -- | ||
16 | Repair an open or a short to ground in glow plug relay ignition feed circuit. Is the action complete? | -- | -- | |
17 | Repair any open or poor connections in the glow plug relay gr Is the action complete? | -- | -- | |
18 |
Did you find a problem? | -- | ||
19 | Check the glow plug relay control circuit for a proper connection at the PCM and replace the terminal if necessary. Did you find a problem? | -- | ||
20 |
Did you find a problem? | -- | ||
21 | Check the glow plug relay signal circuit for a proper connection at the PCM and replace the terminal if necessary. Did you find a problem? | -- | ||
22 | Check for a short to voltage in the glow plug relay signal circuit. Did you find a problem? | -- | ||
23 | Check for a short to voltage in the glow plug control circuit. Did you find a problem? | |||
24 | Repair the open or poor connection on the battery feed circuit. Is action complete? | -- | -- | |
25 | Replace any glow plug that did not illuminate the test light. Is action complete? | -- | -- | |
26 | Repair the open or poor connections in the glow plug harness. Is the action complete? | -- | -- | |
27 | Repair the short to ground in the glow plug harness. Is the action complete? | -- | -- | |
28 | Replace the glow plug relay. Is the action complete? | -- | -- | |
29 |
Important: The new PCM must be programmed. Replace the PCM. Is the action complete? | -- | -- | |
30 |
Does the scan tool indicate the diagnostic Passed? | -- | ||
31 | Does the scan tool display any additional undiagnosed DTCs? | -- | Go to the applicable DTC table | System OK |
