Diagnostic Starting Point - Automatic Transmission Shift Lock Control
Begin the system diagnosis with the Diagnostic System Check - Automatic Transmission Shift Lock Control . 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 diagnostic trouble codes (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 |
|---|---|---|
| Shifter Unlock Cmd. | Special Functions-Output Control | Command turns ON and OFF the controlled ground to the shift lock control solenoid. When ON a ground is supplied to the control circuit of the automatic transmission shift lock control solenoid. |
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 |
| Shifter Lock Fbbk | Chassis Data | High/Low | High |
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 |
| Shifter Inhibit | TCM | Loe TFT/Normal | Normal |
Engine Control Module (ECM)
Diagnostic Trouble Code (DTC) List
| DTC | Diagnostic Procedure | Module(s) |
|---|---|---|
| B2707 | DTC B2707 | Body Control Module (BCM) |
| B2708 | DTC B2708 | Body Control Module (BCM) |
Diagnostic Trouble Code (DTC) List
Circuit Description
The body control module (BCM) controls the automatic transmission shift lock control solenoid by providing a controlled ground 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 body control module (BCM) detects a short to ground when the solenoid is in the OFF state.
Conditions for Running the DTC
- The ignition switch is in the ON position.
- The brake pedal is released.
- The transmission the PARK position.
Conditions for Setting the DTC
The BCM detects the shift lock control solenoid control circuit is grounded 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 A/T shift lock control circuit is shorted to ground, the automatic transmission shift lock control solenoid will be energized. The shift lever will not shift out of PARK position with the brake pedal depressed.
- 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-188770-S18124834412005090200000) in Wiring Systems.
The body control module (BCM) controls the automatic transmission shift lock control solenoid by providing a controlled ground 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 body control module (BCM) detects a short to voltage when the automatic transmission shift lock control solenoid is active.
- The ignition switch is in the ON position.
- The brake pedal is depressed.
- The transmission the PARK position.
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.
- The security light, service light and MIL lamp are always ON with the ignition OFF.
- 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 A/T shift lock control circuit is shorted to battery positive voltage, the automatic transmission shift lock control solenoid will be unlocked. The vehicle will shift out of PARK without depressing the brake pedal.
- 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-188770-S18124834412005090200000) in Wiring Systems.
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-188770-S05143345352005090200000) in Wiring Systems.
- 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-188799-S10478843292005090200000)
- «Shift Lever Can Be Moved without Brake Pedal Depressed»(ref-188799-S00850027412005090200000)