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
--- | --- | --- | --- | ---
Accessory Voltage | 1 | 1 | -- | --
Ignition Lock Cylinder 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 (EPL) system. 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 accessory voltage circuit 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 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

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

• | The ignition lock cylinder control switch is part of the shift lock solenoid/switch assembly.

### Reference Information

#### Schematic Reference

Ignition Lock Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Electronic Park Lock Description and Operation

#### 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 control switch.
2. Verify that a test lamp illuminates between the ground circuit terminal 1 and B+.

⇒ | If the test lamp does not illuminate, test the ground circuit for an open/high resistance.

3. Connect a test lamp between the control circuit terminal 2 and ground.
4. Ignition ON, place the transmission shift selector in PARK then out of PARK. The test lamp should turn ON and OFF when changing between PARK then out of PARK.

⇒ | If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, test or replace the ignition lock cylinder control switch.

⇒ | If the test lamp is always OFF, test the control circuit, and the ignition lock cylinder control switch accessory voltage circuit for a short to ground or open/high resistance. If the circuits test normal, test or replace the ignition lock cylinder control switch.

5. If all circuits test normal, test or replace the ignition lock cylinder control actuator.

### Component Testing

#### Ignition Lock Cylinder Control Switch

1. Ignition OFF, disconnect the harness connector at the ignition lock cylinder control switch.
2. Test for infinite resistance between terminal A and terminal B with the switch in the open position.

⇒ | If less than specified, replace the ignition lock cylinder control switch.

3. Test for less than 2 ohms between terminal A and terminal B with the switch in the closed position.

⇒ | If greater than the specified range, replace the ignition lock cylinder control switch.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Automatic Transmission Shift Lock Control Actuator Replacement