Transmission Control Lever Malfunction
Transmission Control Lever Malfunction
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions)provides an overview of each diagnostic category.
Diagnostic Fault Information
Circuit/System Description
Shift Lock
The body control module (BCM) controls the automatic transmission shift lock control solenoid by providing a battery positive voltage to the solenoid. The BCM utilizes a smart driver to control the voltage supply circuit to the automatic transmission shift lock control solenoid. The smart driver monitors the voltage and current flow of the control circuit.
Reverse Lockout
The reverse lockout system is a safety feature which prevents an inadvertent shift into reverse at speeds above 5 km/h (3 mph). With the ignition ON, battery voltage is supplied directly to the reverse lockout solenoid. At forward speeds above 5 km/h (3 mph), the engine control module (ECM) commands the reverse lockout solenoid ON by grounding the control circuit of the solenoid. This energizes the solenoid and mechanically prevents the shift lever from going from NEUTRAL into the REVERSE position. At forward speeds below 5 km/h (3 mph), the ECM commands the reverse lockout solenoid OFF, de-energizing the solenoid, which allows the shift lever to move into the REVERSE position.
Reference Information
Schematic Reference
Shift Lock Control Schematics (Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector End Views By Name)
Description and Operation
* Automatic Transmission Shift Lock Control Description and Operation (Automatic Transmission Shift Lock Control Description and Operation)
* Reverse Lockout System Description and Operation (Reverse Lockout System Description and Operation)
Electrical Information Reference
* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
Scan Tool Reference
Control Module References (Programming and Relearning)for scan tool information
Circuit/System Verification
1. Ignition ON, while pressing the brake pedal, observe the scan tool Brake Applied Output Signal parameter. The reading should be ON with the brake pedal pressed.
• If not the specified value, refer to Stop Lamps Malfunction (Stop Lamps Malfunction).
2. Press the brake pedal, the vehicle operator should be able to move the shifter lever out of the park position.
3. With the vehicle moving over 5 km/h (3 mph), the vehicle operator should not be able to move the shift lever into the reverse position.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector X1 at the automatic transmission shift lever assembly.
2. Ignition OFF, test for less than 1.0 ohm between the ground circuit terminal C and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Install a test lamp between the ground circuit terminal C and the control circuit terminal B.
4. Ignition ON, command the scan tool BCM Brake To Shift Control output control ON and OFF. The test lamp should turn ON and OFF as commanded.
• If the test lamp is always ON, test the control circuit for short to voltage. If the circuit tests normal, replace the BCM.
• If the test lamp is always OFF, test the control circuit for short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
5. If the circuit tests normal, test or replace the shift lock control solenoid.
6. Ignition OFF, connect the harness connector X1 at the automatic transmission shift lever assembly. Disconnect the harness connector X2 at the automatic transmission shift lever assembly.
7. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal A and ground.
• If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
8. Connect a test lamp between the B+ terminal A and the control circuit terminal B.
9. Command the Reverse Inhibit ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
• If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the ECM.
• If the test lamp is always OFF, test the control circuit for a short to voltage open/high resistance. If the circuit tests normal, replace the ECM.
10. If all circuits test normal, test or replace the shifter assembly.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Transmission Control Replacement (Transmission Control Replacement)
* Control Module References (Programming and Relearning)for BCM and ECM replacement, setup, and programming