Circuit/System Description

The Glow Plug Control Module (GPCM) has the ability to perform internal diagnostics for voltage and output state of the glow plugs. The GPCM monitors the battery voltage of the module's main voltage supply circuit, the Ignition 1 Signal circuit and the Engine Control Module (ECM) Voltage circuit. If the GPCM detects a difference between the GPCM main battery supply circuit and the Ignition 1 Signal circuit greater than 5 V the DTC will set or if the GPCM detects a difference of 3 V between the GPCM main battery supply circuit and the ECM Voltage circuit. The GPCM will send a message to the ECM to set this DTC.