P0380 Glow Plug Feedback Circuit (California)

Diagnostic Chart (Part 1 Of 3):

Diagnostic Chart (Part 2 Of 3):

Diagnostic Chart (Part 3 Of 3):

DIAGNOSTIC AIDS

IMPORTANT: 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 the glow plug relay is stuck in the ON position, check for proper operation to the glow plugs. When the 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 tested for proper torque. The California glow plug system will send the following voltages (signal) to the PCM:

DTC P03680 Glow Plug Feedback Circuit (California):

An intermittent may be caused by the following:
^ Poor connections (terminal tension)
^ Rubbed-through wire insulation
^ Broken wire inside the insulation

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table:
3. This step determines if P0380 is a hard failure.
4. This step determines if there is a short to voltage on the signal circuit.
8. This step determines if there is ignition voltage at the glow plug relay.
10. This step determines if the glow plug control circuit and PCM are working properly.
11. This step determines if there is a short to voltage on the relay control circuit.
13. This step determines if the glow plugs or the glow plug harness is causing the P0380.
29. This step ensures that the replacement PCM, which utilizes an electrically Erasable Programmable Read Only Memory (EEPROM), is programmed when installed.