Important: Vehicle must be in operating condition before performing this procedure.

The glow plug system type learn is used to identify the correct system type (Federal or California). The scan tool will display Federal, California or Not Learned (Engine Data List). For visual verification refer to Component Views. The glow plug system type needs to be relearned when a new calibration has been "flashed" programmed in to the PCM (it is not necessary to relearn a glow plug system type after a PCM has been replaced, the new PCM has the ability to perform an auto learn when system is not present (Not Learned will be displayed on scan tool). If a system type has not been relearned after the PCM has been "flashed" a P0380 will set.

1. Turn the ignition on leaving the engine off.
2. Using the scan tool, select SPECIAL FUNCTIONS, ENGINE OUTPUT FUNCTIONS AND GLOW PLUG SYSTEM LEARN.
3. Activate the Glow Plug System Learn by selecting ON. After the learn function has been preformed NOT LEARNED will be displayed on the scan tool (in this step, the scan tool is clearing the system type).
4. Go back to the Special Functions menu on the scan tool and select Glow Plug.
5. Activate the Glow Plug system by selecting ON (in this step, the glow plug relay is now sending the identifying (signature) voltage to the PCM).
6. The PCM will now be able to identify the correct glow plug system type. For visual verification of the glow plug system, refer to Component Views.
7. Clear the DTC P0380.
8. Allow the PCM to power down for at least 45 seconds.
9. Turn the ignition on leaving the engine off. Using the scan tool to verify that DTC P0380 has not reset.
10. If DTC P0380 reset, perform the following:

•	Check the connections at the glow plug relay.

•	Try again to relearn the glow plug system. If the relearn fails again, refer to P0380.