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For 1990-2009 cars only

Transmission Control Lever Malfunction Column

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

Shift Lock Control Solenoid Control Circuit

B2705 02

1

--

--

Shift Lock Control Solenoid Ground Circuit

--

1

--

--

1. Unable to move gearshift lever with brake pedal depressed

Circuit/System Description

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 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.

Reference Information

Schematic Reference

Shift Lock Control Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

    •  Automatic Transmission Shift Lock Control Description and Operation
    •  Reverse Lockout System Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References 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.
  2. If not the specified value, refer to Stop Lamps Malfunction .
  3. Press the brake pedal, the vehicle operator should be able to move the shifter lever out of the park position.

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the shift lock control solenoid.
  2. Ignition OFF, test for less than 1.0 ohm between the ground circuit terminal A and ground.
  3. If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Install a test lamp between the ground circuit terminal A and the control circuit terminal B.
  5. 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.
  6. 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.
  7. If the circuit tests normal, test or replace the shift lock control solenoid.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Automatic Transmission Shift Lock Control Actuator Replacement
    •  Control Module References for BCM replacement, setup, and programming

Transmission Control Lever Malfunction Floor

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

Brake Transmission Shift Interlock Solenoid Control Circuit

2

2

2

--

Shift Lock Control Solenoid Ignition Voltage

2

2

--

--

Shift Lock Control Solenoid Ground Circuit

--

2

2

--

Reverse Lockout Solenoid Ignition Voltage

1

1

--

--

Reverse Lockout Solenoid Control

1

1

--

--

1. Reverse Lockout Malfunction

2. Shift Lock Control Solenoid Malfunction

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

Connector End View Reference

Component Connector End Views

Description and Operation

    •  Automatic Transmission Shift Lock Control Description and Operation
    •  Reverse Lockout System Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References 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.
  2. If not the specified value, refer to Stop Lamps Malfunction .
  3. Press the brake pedal, the vehicle operator should be able to move the shifter lever out of the park position.
  4. 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.
  3. If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal A and ground.
  5. If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
  6. While pressing the brake pedal, verify that a test lamp illuminates between the control circuit terminal B and B+.
  7. 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.
  8. 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.
  9. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal A and ground.
  10. If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
  11. Connect a test lamp between the B+ terminal A and the control circuit terminal B.
  12. 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.
  13. 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.
  14. If all circuits test normal, test or replace the shifter assembly.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Transmission Control Replacement
    •  Control Module References for BCM and ECM replacement, setup, and programming