For 1990-2009 cars

### 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 P064C: Glow Plug Control Module Performance

### Circuit/System Description

This DTC applies to internal microprocessor integrity conditions within the glow plug control module.

### Conditions for Running the DTC

• | The ignition is ON.

• | The battery voltage is between 9-16 volts.

• | The DTC runs once per ignition cycle when the above condition is met.

### Conditions for Setting the DTC

The ECM detects a glow plug control module malfunction.

### Action Taken When the DTC Sets

DTC P064C is a Type A DTC.

### Conditions for Clearing the DTC

DTC P064C is a Type A DTC.

### Reference Information

#### DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

### Circuit/System Verification

Operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records List. DTC P064C should not set.

### Circuit/System Testing

1. Ignition OFF, and the MAIN fuse removed, disconnect the harness connector at the glow plug control module.
2. Test for less than 5 ohms of resistance between the ground circuit terminal 7 and ground.

⇒ | If greater than the specified range, repair the ground circuit for an open/high resistance.

3. Test for greater than 1 ohm of resistance between each of the glow plug circuit terminals 1-4 and ground.

⇒ | If less than the specified range, repair the glow plug circuit for a short to ground.

4. Install the MAIN fuse. Ignition ON, verify a test lamp illuminates between the ignition voltage circuit terminal 6 and ground.

⇒ | If the test lamp does not illuminate, repair the ignition voltage circuit for a short to ground or an open/high resistance.

5. If all circuits test normal, replace the glow plug control module.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.