Transmission Control Lever Malfunction (Floor)
Transmission Control Lever Malfunction (Floor)
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
Shift Lock
The automatic transmission shift lock control system is a safety device that prevents an inadvertent shift out of PARK when the engine is running. The driver must press the brake pedal before moving the shift lever out of the PARK position. The shift lock solenoid is a 3 wire motor. With the ignition ON battery voltage is supplied to the shift lock control solenoid from the SHFTR SOL fuse. The solenoid is grounded at G304. When the brake pedal is pressed, the body control module (BCM) sends a voltage signal to the shift lock control solenoid through the shift lock solenoid control circuit. This signal mechanically unlocks the shift lever allowing the driver to move the shift lever out of the PARK position.
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 from the HTD/COOL/IGN3 fuse. 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 ([1][2]Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
* Automatic Transmission Shift Lock Control Description and Operation (Column Shift) (Automatic Transmission Shift Lock Control Description and Operation (Column Shift))Automatic Transmission Shift Lock Control Description and Operation (Floor Shift) (Automatic Transmission Shift Lock Control Description and Operation (Floor Shift))
* Reverse Lockout System Description and Operation (Reverse Lockout System 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
Programming and Relearning (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. 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.
4. While pressing the brake pedal, verify that a test lamp illuminates between the control circuit terminal B and B+.
• If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance. If all circuits test normal, replace the BCM.
5. 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.
6. 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.
7. Connect a test lamp between the B+ terminal A and the control circuit terminal B.
8. 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.
9. 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)
* Programming and Relearning (Programming and Relearning) for BCM and ECM replacement, setup, and programming