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.

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Park Switch Ignition 1 Voltage | 1 | 1 | -- | --
Steering Column Key Cylinder Lock Solenoid Control | 1 | 1 | 2 | --
Ground | -- | 1 | -- | --
1. Ignition key will not turn to OFF with vehicle in park. 2. Ignition key will turn to OFF with vehicle out of park.

### Circuit/System Description

If the vehicle is equipped with automatic transmission and a floor mounted console gear shift, it has an electronic park lock system (EPL). The EPL system purpose is to prevent the ignition key from being turned to the OFF position when the transmission is in any position other than PARK and the vehicle may still be moving. The EPL system consists of an ignition lock cylinder solenoid, and a park position switch that is located in the A/T shift lock control switch. The ignition lock cylinder solenoid contains a pin that is spring loaded to mechanically prevent the ignition key cylinder from being turned to the lock position when it is not energized. The park position switch receives voltage from the body control module (BCM) when the ignition is turned ON. When the transmission shift selector is in PARK, the park position switch closes and energizes the ignition lock cylinder solenoid (actuator) retracting the pin, allowing the ignition switch to be turned OFF. If vehicle power is lost, and/or the transmission is not in the Park position the operator will not be able to turn the ignition key to the lock position and will not be able to remove the ignition key from the column.

### Diagnostic Aids

• | Check for the proper operation of the transmission shift selector.

• | Manually pushing in the ignition lock cylinder solenoid will allow the ignition key to be turned to OFF.

• | The ignition lock cylinder solenoid is part of the ignition lock cylinder case.

• | The park switch is part of the shift lock solenoid/switch assembly.

### Reference Information

#### Schematic Reference

Ignition Lock Schematics

#### Connector End View Reference

Master Electrical Component List

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the ignition lock cylinder solenoid.
2. Test for less than 1.0 ohm of resistance between the ground circuit of the connector and ground.

⇒ | If greater than 1.0 ohm, test the ground circuit for an open/high resistance.

3. Ignition ON, shift selector in PARK then out of PARK, verify that a test lamp illuminates in PARK and does not illuminate out of PARK between the steering column key cylinder lock solenoid control circuit and ground.

⇒ | If the test lamp does not illuminate properly, test the solenoid control and park switch ignition voltage circuits for a short to ground, open/high resistance or short to voltage. If the circuits test normal, replace the park switch.

4. If all circuits test normal, test or replace the ignition lock cylinder solenoid.

### Component Testing

#### Park Switch

1. Ignition OFF, disconnect the harness connector at the park switch.
2. Test for infinite resistance between the output terminal and the ignition terminal with the switch in the open position.

⇒ | If not the specified value, replace the park switch.

3. Test for less than 2 ohms of resistance between the output terminal and the ignition terminal with the switch in the closed position.

⇒ | If greater than the specified value, replace the park switch.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Shift Lock Control Solenoid Replacement

• | Ignition Lock Cylinder Case Replacement