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 P161E 01: Glow Plug Positive Voltage 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 between 9-16 volts.

• | The DTC runs once per ignition cycle when the above conditions are met.

### Conditions for Setting the DTC

The ECM detects the glow plug module is not powered up for greater than 5 seconds.

### Action Taken When the DTC Sets

DTC P161E is a Type C DTC.

### Conditions for Clearing the DTC

DTC P161E 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

1. Ignition On, observe the DTC information with a scan tool. DTC P161E should not set.
2. 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

1. Ignition OFF, disconnect the harness connector at the glow plug control module.
2. Ignition ON, verify a test lamp illuminates between the battery voltage circuit terminal 30 and ground.

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

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

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.