• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
• | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
• | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Battery Positive Voltage | P064C | P064C | -- | -- |
Ignition 1 Voltage | P064C | P064C | -- | -- |
Circuit | Normal Range | Short to Ground | Open | Short to Voltage |
---|---|---|---|---|
Operating Conditions: Ignition ON | ||||
Battery Positive Voltage | Battery Voltage | 0 Volts | 0 Volts | -- |
The glow plug control module (GPCM) has the ability to perform internal diagnostics for voltage and output state of the glow plugs. The GPCM will send a message to the engine control module (ECM) to set this DTC.
• | The ignition is ON. |
• | DTC P064C runs continuously. |
• | The GPCM detects a variation between the main battery supply to the GPCM and battery supply to the ECM, or an internal condition for 3 second. |
• | The GPCM detects a low voltage condition on the ignition 1 voltage circuit tot he GPCM. |
• | The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails. |
• | The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records. |
• | The control module turns OFF the MIL after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
• | 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 emission related diagnostic. |
• | Clear the MIL and the DTC with a scan tool. |
⇒ | If the Ignition 1 Signal parameter is not battery voltage, test the battery positive voltage circuit to the glow plug control module terminal C1/A for an open or short to ground. If the circuit tests normal, replace the GPCM. |
⇒ | If the test lamp does not illuminate, test the ignition 1 voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the GPCM. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for GPCM replacement, setup, and programming