P0683 - Glow Plug Control Module (GPCM) To Powertrain Control Module (Pcm) Communication Circuit

P0683 - GLOW PLUG CONTROL MODULE (GPCM) TO POWERTRAIN CONTROL MODULE (PCM) COMMUNICATION CIRCUIT

Description:	The PCM carries out a functional key ON, engine running (KOER) self-test for the glow plug system. During that test the PCM enables the GPCM and monitors the GPCM/PCM communication circuit for concerns. When the PCM detects a concern with a GPCM/PCM communication circuit, the DTC is set.
Possible Causes:	GPCM/PCM communication circuit open in the harness GPCM/PCM communication circuit short to ground in the harness GPCM/PCM communication circuit short to voltage in the harness
Diagnostic Aids:	Diagnose DTC P0670 before diagnosing DTC P0683.
Application		Key On Engine Off	Key On Engine Running	Continuous Memory
All		refer to PINPOINT TEST AF .