Ignition Can/Cannot Be Turned Off with Transmission in Any Gear
Ignition Can/Cannot Be Turned Off with Transmission in Any Gear
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.
Diagnostic Fault Information
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 control actuator, and a park position switch that is located in the A/T shift lock control switch. The ignition lock cylinder control actuator 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 control 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
* Manually pushing in the ignition lock cylinder control actuator pin will allow the ignition key to be turned to OFF.
* The park switch is part of the shift lock solenoid/switch assembly.
Reference Information
Schematic Reference
Ignition Lock Schematics (Ignition Lock Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
Electronic Park Lock Description and Operation (Electronic Park Lock Description and Operation)
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the ignition lock cylinder control actuator.
2. Test for less than 1.0 ohm between the ground circuit terminal B and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Connect a test lamp between the control circuit terminal A and ground.
4. Ignition ON, 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 stays illuminated, test the control circuit for a short to voltage. If the circuit tests normal, test or replace the park switch.
• If the test lamp does not illuminate, test the control, and park switch accessory voltage circuits for a short to ground or open/high resistance. If the circuits test normal, test or replace the park switch.
5. If all circuits test normal, test or replace the ignition lock cylinder control actuator.
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 input terminal with the switch in the open position.
• If not the specified value, replace the park switch.
3. Test for less than 1 ohm between the output terminal and the input 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 (Verification Tests) after completing the diagnostic procedure.
* Transmission Control Replacement (4T65-E - Automatic Transmission)
* Ignition Lock Cylinder Control Solenoid Replacement (Ignition Lock Cylinder Control Solenoid Replacement)