Diagnostic Instructions
| • | 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. |
DTC Descriptors
DTC P0671 02: Glow Plug 1 Control Circuit Short to GroundDTC P0671 04: Glow Plug 1 Control Circuit Open Circuit
DTC P0672 02: Glow Plug 2 Control Circuit Short to Ground
DTC P0672 04: Glow Plug 2 Control Circuit Open Circuit
DTC P0673 02: Glow Plug 3 Control Circuit Short to Ground
DTC P0673 04: Glow Plug 3 Control Circuit Open Circuit
DTC P0674 02: Glow Plug 4 Control Circuit Short to Ground
DTC P0674 04: Glow Plug 4 Control Circuit Open Circuit
Circuit/System Description
The glow plug controller is a solid state device which operates the glow plugs. The temperature and the power consumption is controlled between the engine control module (ECM) and the glow plug controller within a wide range to suit the engine's pre-heating requirements. The ECM controls the glow plug module with a pulse-width modulated (PWM) control circuit. The glow plug initial ON time will vary based on the system voltage and temperature. Lower temperatures cause longer ON times.
Conditions for Running the DTC
| • | The ignition is ON, or the engine is running. |
| • | The ignition voltage is less than 16 volts. |
| • | The DTCs run once per ignition cycle when the above conditions are met. |
Conditions for Setting the DTC
The ECM detects an open or a short to ground on a glow plug control circuit for greater than 6 seconds.
Action Taken When the DTC Sets
DTC P0671, P0672, P0673, P0674 are Type C DTCs.
Conditions for Clearing the DTC
DTC P0671, P0672, P0673, P0674 are Type C DTCs.
Reference Information
Schematic Reference
Connector End View Reference
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- Ignition ON, observe the DTC information with a scan tool. DTC P0671, P0672, P0673, or P0674 should not set.
- Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
- Ignition OFF, and the MAIN fuse removed, disconnect the harness connector at the glow plug control module.
- Test for 1-2.5 ohms of resistance between the appropriate glow plug control circuit terminal and ground.
- If all circuits test normal, test or replace the glow plug control module.
| ⇒ | If less than the specified range, test the control circuit for a short to ground. If the circuit tests normal, replace the Glow Plug. |
| ⇒ | If greater than the specified range, test the control circuit for an open/high resistance. If the circuit tests normal, replace the Glow Plug. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
