Federal RPO FE9, NG1

DTC P0380 (FEDERAL WITH RPO CODE 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 stores the DTC information into memory when the diagnostic runs and fails.
- The malfunction indicator lamp (MIL) will not illuminate.
- The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
- The driver information center, if equipped, may display a message.

CONDITIONS FOR CLEARING THE DTC
- 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 non-emission related diagnostic.
- Clear 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

Steps 1-2:

Steps 3-5:

Steps 6-8:

Steps 9-12:

Steps 13-19:

Steps 20-22:

The numbers below refer to the step numbers on the diagnostic table.
2. This step will determine if DTC P0380 is a hard failure.
3. This step determines if there is a relay control circuit or ECM fault that will not energize the relay.