Transmission Control Lever Malfunction Floor Shift

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 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 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.

Schematic Reference

Shift Lock Control Schematics

Connector End View Reference

Shift Lock Control Connector End Views

Description and Operation

Electrical Information Reference

Scan Tool Reference

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 .

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.

1. Ignition OFF, disconnect the harness connector C1 at the Automatic Transmission Shift Lever assembly.
2. Ignition OFF, test for less than 1.0 ohm of resistance 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 B+ circuit terminal A and ground.

⇒	If the test lamp does not illuminate, test the B+ 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 ground.

⇒	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, test or replace the BCM.

5. Connect the harness connector C1 at the Automatic Transmission Shift Lever assembly.
6. Ignition OFF, disconnect the harness connector C2 at the Automatic Transmission Shift Lever assembly.
7. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal A and ground.

⇒	If the test lamp does not illuminate, test the B+ 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.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Transmission Control Lever Malfunction Column Shift

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 solenoid is grounded at G300. When the brake pedal is pressed, the 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.

Schematic Reference

Shift Lock Control Schematics

Connector End View Reference

Shift Lock Control Connector End Views

Description and Operation

Automatic Transmission Shift Lock Control Description and Operation

Electrical Information Reference

Scan Tool Reference

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 .

2. Press the brake pedal, the vehicle operator should be able to move the shifter lever out of the park position.

1. Ignition OFF, disconnect the harness connector at the Automatic Transmission Shift Lever assembly.
2. Ignition OFF, test for less than 1.0 ohm of resistance between the ground circuit terminal B and ground.

⇒	If greater than the specified range, test the ground circuit for an open/high resistance.

3. While pressing the brake pedal, verify that a test lamp illuminates between the control circuit terminal A and ground.

⇒	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, test or replace the BCM.

4. If all circuits test normal, test or replace the shift lock actuator.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.