Service Information

Cruze

DTC P0670

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 Descriptor

DTC P0670 00: Glow Plug Control Module Control Circuit

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 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 between 9-16 V.

•	The DTCs run once per ignition cycle when the above conditions are met.

Conditions for Setting the DTC

The ECM detects an open, short to ground, or a short to voltage on the glow plug module control circuit for greater than 0.5 s.

Action Taken When the DTC Sets

DTC P0670 00 is a Type C DTC.

Conditions for Clearing the DTC

DTC P0670 00 is a Type C DTC.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

•	Circuit Testing

•	Connector Repairs

•	Testing for Intermittent Conditions and Poor Connections

•	Wiring Repairs

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 P0670 00 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, disconnect the harness connectors at the K34 Glow Plug Control Module.
Ignition ON, test for greater than 10 V between the K34 Glow Plug Control Module control circuit terminal 2 X1 and ground.

⇒	If less than the specified range, test the control circuit for an open or a short to ground. If the circuit tests normal, replace the K20 Engine Control Module.

Test the alternating current (AC) frequency from the K34 Glow Plug Control Module control circuit terminal 2 X1. Command the glow plug control module ON with a scan tool. Verify the AC frequency is between 30-35 Hz.

⇒	If less than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module.

⇒	If greater than the specified range, test the control circuit for a high resistance. If the circuit tests normal, replace the K20 Engine Control Module.

If the circuit tests normal, test or replace the K34 Glow Plug Control Module.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

•	Glow Plug Controller Replacement

•	Control Module References for ECM replacement, setup, and programming