DIAGNOSTIC CODE INDEX
| DTC | Description |
|---|---|
| DTC B2707 | Gearshift Unlock Circuit Low |
| DTC B2708 | Gearshift Unlock Circuit High |
DIAGNOSTIC CODE INDEX
Begin the system diagnosis with the Diagnostic System Check - Vehicle . The Diagnostic System Check will provide the following information
- The identification of the control modules which command the system
- The ability of the control modules to communicate through the serial data circuit
- The identification of any stored DTCs and their status
The use of the Diagnostic System Check will identify the correct procedure for diagnosing the system and where the procedure is located.
Scan Tool Output Controls
| Scan Tool Output Control | Additional Menu Selection(s) | Description |
|---|---|---|
| Brake to Shift Relay | Select Transmission Special Functions-Output Control | Commands the brake to shift relay ON for 5 seconds and OFF. Turns ON and OFF the brake to shift relay. |
Scan Tool Output Controls
Scan Tool Data List
| Scan Tool Parameter | Data List | Units Displayed | Typical Data Value |
|---|---|---|---|
| Operating Conditions: Ignition ON, with the engine OFF. Transmission shift lever in the PARK position. | |||
| Battery 1 | Ignition | Volts | 0-25 V |
| Power Mode | Ignition | OFF/ACCY/RUN/CRANK | RUN |
Body Control Module (BCM)
| Scan Tool Parameter | Data List | Units Displayed | Typical Data Value |
|---|---|---|---|
| Operating Conditions: Ignition ON, with the engine OFF. Transmission shift lever in the PARK position. | |||
| Battery 1 | TCM | Volts | 0-25 V |
| Command Gear | TCM | Park/Rev/Neu/4/3/2/1 | Park |
| TCC Brake Switch | TCM | ON/OFF | OFF |
Engine Control Module (ECM)
Circuit Description
The body control module (BCM) controls the automatic transmission shift lock control solenoid by providing controlled battery voltage to the automatic transmission shift lock control solenoid. The BCM utilizes a smart driver to monitor the voltage and current flow of the automatic transmission shift lock control solenoid control circuit. DTC B2707 will set when the BCM detects a short to ground or open circuit when the solenoid is in the ON state.
DTC Descriptor
This diagnostic procedure supports the following DTC
DTC B2707 Gearshift Unlock Circuit Low
Conditions for Running the DTC
- The ignition switch is in the ON position.
- The brake pedal is released.
- The transmission is in the PARK position.
Conditions for Setting the DTC
The BCM detects the control circuit of the shift lock control solenoid is grounded or opened for a minimum of 1 second.
Action Taken When the DTC Sets
The BCM disables shift lock control solenoid operation until the next key cycle.
Conditions for Clearing the DTC
- A current DTC B2707 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.
Diagnostic Aids
- If the control circuit of the automatic transmission shift lock solenoid is opened or shorted to ground the shift lever will not lock in the PARK position.
- Perform the tests while wiggling the wires and connectors. This may often cause an intermittent malfunction to appear. Refer to «Testing for Intermittent Conditions and Poor Connections»(ref-266894-S04712775072007100900000) .
The body control module (BCM) controls the automatic transmission shift lock control solenoid by providing controlled voltage to the automatic transmission shift lock control solenoid. The BCM utilizes a smart driver to monitor the voltage and current flow of the automatic transmission shift lock control solenoid control circuit. DTC B2708 will set when the BCM detects a short to voltage when the automatic transmission shift lock control solenoid is inactive.
This diagnostic procedure supports the following DTC
DTC B2708 Gearshift Unlock Circuit High
- The ignition switch is in the ON position.
- The shift lock control solenoid is inactive.
The BCM detects a short to voltage at the control circuit driver of the automatic transmission shift lock control solenoid for a minimum of 1 second.
The BCM disables shift lock control solenoid operation until the next key cycle.
- A current DTC B2708 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.
- If the voltage control circuit of the automatic transmission shift lock control solenoid is shorted to battery positive voltage, the shift lever will be locked in the PARK position.
- Perform the tests while wiggling the wires and connectors. This may often cause an intermittent malfunction to appear. Refer to «Testing for Intermittent Conditions and Poor Connections»(ref-266894-S04712775072007100900000) .
Visual/Physical Inspection
- Inspect for aftermarket devices which could affect the operation of the automatic transmission shift lock control system. Refer to «Checking Aftermarket Accessories»(ref-266894-S42790233922007100900000) .
- Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
Symptom List
Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom
- «Shift Lever Does Not Move with Brake Pedal Depressed»(ref-266919-S07398612302007100900000)
- «Shift Lever Can Be Moved without Brake Pedal Depressed»(ref-266919-S24002164422007100900000)