For 1990-2009 cars

### 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.

### DTC Descriptors

DTC B2705 02: Gearshift Unlock Circuit Short to Ground
DTC B2705 05: Gearshift Unlock Circuit Short to Battery or Open

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
A/T Shift Lock Control Solenoid Supply Voltage | B2705 02 | B2705 05 | B2705 05 | --
Transmission Shift Select Switch (Park) Signal | -- | B2705 05 | -- | --

### 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 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.

### Conditions for Running the DTC

• | Ignition ON.

• | The brake pedal is pressed.

• | The transmission is in the PARK position.

### Conditions for Setting the DTC

• | DTC B2705 02 sets if the automatic transmission shift lock control solenoid control circuit is shorted to ground.

• | DTC B2705 05 sets if the automatic transmission shift lock control solenoid control circuit is open or shorted to voltage.

### 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 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

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Automatic Transmission Shift Lock Control 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 Lamp parameter. The reading should be ON with the brake pedal pressed.

⇒ | If not the specified parameter, 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.

### 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 transmission shift select switch (park) signal circuit terminal B 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.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for BCM replacement, setup, and programming