B2705
DTC B2705
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.
DTC Descriptor
DTC B2705 02
- Gearshift Unlock Circuit Short to Ground
Diagnostic Fault Information
Circuit/System Description
The body control module (BCM) controls the automatic transmission shift lock control solenoid by providing a battery positive voltage to the solenoid. The BCM controls the voltage supply circuit to the automatic transmission shift lock control solenoid.
Conditions for Running the DTC
* The ignition switch is in the ON position.
* The brake pedal is pressed.
* The transmission is in the PARK position.
Conditions for Setting the DTC
The DTC sets if there is a short to ground in the automatic transmission shift lock control solenoid control circuit.
Action Taken When the DTC Sets
The BCM will not attempt to enable the voltage supply circuit of the automatic transmission shift lock control solenoid until the next key cycle.
Conditions for Clearing the DTC
* A current DTC B2705 will clear when the malfunction is no longer present and the ignition switch is cycled.
* All BCM history codes will clear after 100 ignition cycles with no current codes active during the 100 ignition cycles.
Reference Information
Schematic Reference
Shift Lock Control Schematics (Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
Automatic Transmission Shift Lock Control Description and Operation (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
Programming and Relearning (Programming and Relearning) for scan tool information
Circuit/System Verification
1. Use a scan tool to verify there are no brake pedal position sensor and/or transmission internal mode switch (IMS) DTCs set that could cause the BCM not to provide battery voltage to the A/T shift lock solenoid.
2. 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 parameter, refer to Stop Lamps Malfunction (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 ohm between the ground circuit terminal F 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 F and the control circuit terminal E.
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 all circuits test normal, replace the shift lock control solenoid.
Component Testing
1. Install a 10 A fused jumper wire between the control circuit terminal E and 12 volts. Install a jumper wire between the ground circuit terminal F and ground.
2. Verify the solenoid turns ON and OFF.
• If the function does not perform as specified, replace the shift lock actuator.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Automatic Transmission Shift Lock Control Actuator Replacement (Traverse) (Service and Repair)Automatic Transmission Shift Lock Control Actuator Replacement (Acadia, Enclave, OUTLOOK) (Service and Repair)
* Control Module References (Programming and Relearning) for BCM replacement, setup, and programming