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 B2708: Gearshift Unlock Circuit HighDiagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Shift Lock Control Solenoid Control | B2707 | 1 | B2708 | -- |
Shift Lock Control Solenoid Ground | -- | 1 | -- | -- |
1. Unable to move shift lever with brake pedal depressed. | ||||
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
| • | The ignition switch is in the ON position. |
| • | The brake pedal is pressed. |
| • | The transmission gear selector 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. |
| • | A history DTC will clear after 100 ignition cycles with no current DTC active during the 100 ignition cycles. |
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Automatic Transmission Shift Lock Control Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- Ignition ON, vehicle in PARK, observe the scan tool TCM TR SW parameter. The parameter should indicate PARK.
- Observe the scan tool TCM Brake Switch parameter while pressing and releasing the brake pedal. The parameter should change between Applied and Released.
| ⇒ | If not the specified value, refer to Range Selector Displays Incorrect Range . |
| ⇒ | If the parameter does not change between the specified values, refer to Stop Lamps Malfunction . |
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the shift lock control solenoid.
- Test for less than 1.0 ohm between the ground circuit terminal B and ground.
- Connect a test lamp between the ground circuit terminal B and the control circuit terminal A.
- Ignition ON, command the scan tool BCM Brake to Shift Relay output control ON and OFF. The test lamp should turn ON and OFF as commanded.
- If the circuit tests normal, replace the transmission control.
| ⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
| ⇒ | 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. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for BCM replacement, setup and programming |
