Automatic Transmission Shift Lock Control Schematic Icons
Automatic Transmission Shift Lock Control Schematic Icons Icon Icon Definition IMPORTANT: Twisted-pair wires provide an effective "shield" that helps protect sensitive electronic components from electrical interference. If the wires were covered with shielding, install new shielding. Refer to Splicing Twisted or Shielded Cable in Wiring Systems. In order to prevent electrical interference from degrading the performance of the connected components, you must maintain the proper specification when making any repairs to the twisted-pair wires shown : The wires must be twisted a minimum of 9 turns per 31 cm (12 in) as measured anywhere along the length of the wires The outside diameter of the twisted wires must not exceed 6.0 mm
Scheme 72
Scheme 73
Scheme 74
| Callout | Component Name |
|---|---|
| 1 | A/T Shift Lock Control Solenoid |
| 2 | PRNDL Lamp |
| 3 | C241 |
| 4 | C240 |
Automatic Transmission Shift Lock Control Connector End Views
A/T Shift Lock Control Solenoid (w/o D55) Connector Part Information OEM: 12052832 Service: 12101825 2-Way F Metri-Pack 150 Series (BK) Pin Wire Color Circuit No. Function A D-GN/WH 1135 A/T Shift Lock Solenoid Supply Voltage B BK/WH 1551 Ground
Diagnostic Starting Point - Automatic Transmission Shift Lock Control
Begin the system diagnosis with the Diagnostic System Check - Vehicle in Vehicle DTC Information. 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 |
|---|---|---|
| Shift Lock Control Output | Special Functions-Output Control | The body control module (BCM) controls the voltage to the automatic transmission shift lock control solenoid ON or OFF for 5 seconds. |
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. Brake pedal released. | |||
| Battery Voltage | BCM Data | 0-15 volts | 14 volts |
| Ignition 1 | Inputs | ON/OFF | ON |
| Brake Switch Input | Inputs | ON/OFF | OFF |
| Shift Lock Control Output | Inputs | ON/OFF | ON |
| Remote Start | Input | ON/OFF | OFF |
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. Brake pedal released. | |||
| Current Gear | Transmission Data | ||
| TR Sw. A/B/C/P | Transmission Data | Park, Park/Reverse, Reverse, Reverse/Neutral, Neutral, Neutral/Drive 4, Drive 4, Drive 4/Drive 3, Drive 3, Drive 3/Drive 2, Drive 2, Drive 2/Drive 1, Drive 1, Invalid, Open | |
| TCC Brake Switch | ON/OFF | OFF | |
Powertrain Control Module (PCM)
Circuit Description
The body control module (BCM) controls the A/T shift lock control solenoid by providing battery voltage to the A/T shift lock control solenoid. The BCM utilizes a smart driver to control the voltage supplied to the A/T shift lock control solenoid. The smart driver monitors the voltage and current flow of the control circuit.
DTC Description
This diagnostic procedure supports the following DTC
DTC B2705 Gearshift Unlock Circuit
Conditions for Running the DTC
- The ignition switch is in the ON position.
- The brake pedal is depressed.
- The transmission the PARK position.
Conditions for Setting the DTC
The BCM output driver detects an open or short in the output control circuit.
Action Taken When the DTC Sets
The BCM disables the output control until the next ignition 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.
Diagnostic Aids
- 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 control solenoid.
- If the automatic transmission shift lock control circuit is shorted to battery positive voltage, the automatic transmission shift lock control solenoid will be inoperative. 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»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing) .
Test Description
The numbers below refer to the step numbers on the diagnostic table.
- 2: Listen for an audible click when the A/T shift lock control solenoid operates. Command both the ON and OFF states. Repeat the commands as necessary.
- 3: Tests for battery voltage at the control circuit of the A/T shift lock control solenoid.
- 4: Tests for an open or short to ground at the control circuit of the A/T shift lock control solenoid.
- 5: Tests for an open at the ground circuit of the A/T shift lock control solenoid.
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Automatic Transmission Shift Lock Control Schematics Connector End View Reference: Automatic Transmission Shift Lock Control Connector End Views or Computer/Integrating Systems Connector End Views in Computer/Integrating Systems | |||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
| 2 | Install a scan tool. Turn ON the ignition, with the engine OFF. With a scan tool, command the brake to shift control (if column shift) or console shift BTSI relay (if console shift) output control ON and OFF. With a scan tool, observe the BTSI solenoid (if column shift) or console shift BTSI relay (if console shift) parameter in the body control module (BCM) data list. Does the A/T shift lock control solenoid turn ON and OFF with each command? | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 |
| 3 | Turn OFF the ignition. Disconnect the A/T shift lock control solenoid. Connect a test lamp between the shift lock solenoid control circuit at the connector of the A/T shift lock solenoid and a good ground. Turn ON the ignition, with the engine OFF. With a scan tool, command the brake to shift control (if column shift) or console shift BTSI relay (if console shift) output control ON and OFF several times. Does the test lamp illuminate ON and OFF with each command? | Go to Step 5 | Go to Step 4 |
| 4 | Test the control circuit of the A/T shift lock control solenoid for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 10 | Go to Step 7 |
| 5 | Test the A/T shift lock control solenoid ground circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 10 | Go to Step 6 |
| 6 | Inspect for poor connections at the harness connector of the A/T shift lock control solenoid. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 10 | Go to Step 8 |
| 7 | Inspect for poor connections at the harness connector of the body control module (BCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 10 | Go to Step 9 |
| 8 | Replace the A/T shift lock control solenoid. Refer Automatic Transmission Shift Lock Actuator Replacement . Did you complete the replacement? | Go to Step 10 | |
| 9 | IMPORTANT: Perform the set up procedures for the BCM. Replace the BCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup and programming.Did you complete the replacement? | Go to Step 10 | |
| 10 | Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Does the DTC reset? | Go to Step 2 | System OK |
| IMPORTANT |
|---|
| Perform the set up procedures for the BCM. |
DTC B2705
Symptoms - Automatic Transmission Shift Lock Control
| IMPORTANT | The following steps must be completed before using the symptom tables. |
- Perform the «Diagnostic System Check - Vehicle»(/buick/lacrosse/i-2004-2009/remont/oem-general-information/#vehicle-dtc-information) in Vehicle DTC Information before using the Symptom Tables in order to verify that all of the following are true: There are no DTCs set. The control modules can communicate via the serial data link.
- Review the system operation in order to familiarize yourself with the system functions. Refer to «Automatic Transmission Shift Lock Control Description and Operation»(/buick/lacrosse/i-2004-2009/remont/automatic-trans/#shift-interlock-system__automatic-transmission-shift-lock-control-description) .
Visual/Physical Inspection
- Inspect for aftermarket devices which could affect the operation of the automatic transmission shift lock control. Refer to «Checking Aftermarket Accessories»(/buick/lacrosse/i-2004-2009/remont/body-electrical/#how-to-diagnosis-repair-the-wiring-systems-testing__checking-aftermarket-accessories) in Wiring Systems.
- Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
Intermittent
Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
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»(/buick/lacrosse/i-2004-2009/remont/automatic-trans/#shift-interlock-system__shift-lever-does-not-move-with)
- «Shift Lever Can Be Moved without Brake Pedal Depressed»(/buick/lacrosse/i-2004-2009/remont/automatic-trans/#shift-interlock-system__shift-lever-can-be-moved-without)
Shift Lever Does Not Move with Brake Pedal Depressed
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Automatic Transmission Shift Lock Control Schematics Connector End View Reference: Automatic Transmission Shift Lock Control Connector End Views | |||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
| 2 | Turn ON the ignition, with the engine OFF. Apply the parking brake and block the wheels. Press and hold the brake pedal. Attempt to move the shift lever out of the PARK position. Does the shift lever move out of the PARK position? | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 |
| 3 | Turn OFF the ignition. Install and scan tool. Turn ON the ignition, with the engine OFF. Press and release the brake pedal several times while observing the brake to shift output parameter in the body control module (BCM) output data list. Does the scan tool display ON and OFF status? | Go to Step 4 | Go to Step 6 |
| 4 | Turn OFF the ignition. Disconnect the electrical connector of the automatic transmission shift lock control solenoid. Turn ON the ignition, with the engine OFF. Press and hold the brake pedal. Attempt to move the shift lever out of the PARK position. Does the shift lever move out of the PARK position? | Go to Step 5 | Go to Step 7 |
| 5 | Test the control circuit of the automatic transmission shift lock control solenoid for a short to battery positive voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 11 | Go to Step 8 |
| 6 | Press and release the brake pedal several times while observing the brake apply sensor input parameter in the powertrain control module (PCM) input data list. Does the scan tool display ON and OFF status of the input parameter? | Go to Step 8 | Go to Stop Lamps Inoperative in Lighting Systems |
| 7 | Inspect for poor connections at the harness connector of the automatic transmission shift lock control solenoid. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 11 | Go to Step 9 |
| 8 | Inspect for poor connections at the harness connector of the BCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 11 | Go to Step 10 |
| 9 | Replace the automatic transmission shift lock control solenoid. Refer Automatic Transmission Shift Lock Actuator Replacement . Did you complete the replacement? | Go to Step 11 | |
| 10 | IMPORTANT: Perform the set up procedures for the BCM. Replace the BCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup and programming.Did you complete the replacement? | Go to Step 11 | |
| 11 | Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Does the DTC reset? | Go to Step 2 | System OK |
| IMPORTANT |
|---|
| Perform the set up procedures for the BCM. |
Shift Lever Does Not Move with Brake Pedal Depressed
Shift Lever Can Be Moved without Brake Pedal Depressed
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Automatic Transmission Shift Lock Control Schematics Connector End View Reference: Automatic Transmission Shift Lock Control Connector End Views | |||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
| 2 | Install a scan tool. Turn ON the ignition, with the engine OFF. With a scan tool, command the brake to shift output control ON and OFF. Does the automatic transmission shift lock control solenoid turn ON and OFF with each command? | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 |
| 3 | Turn OFF the ignition. Disconnect the automatic transmission shift lock control solenoid. Connect a test lamp between the shift lock control solenoid ground circuit at the connector of the shift lock control solenoid and battery positive voltage. Turn ON the ignition, with the engine OFF. Does the test lamp illuminate? | Go to Step 4 | Go to Step 10 |
| 4 | Turn OFF the ignition. Connect a test lamp between the shift lock solenoid control circuit and the shift lock solenoid ground circuit at the connector of the shift lock control solenoid. With a scan tool, command the shift lock control solenoid ON and OFF several times. Does the test lamp turn ON and OFF with each command? | Go to Step 8 | Go to Step 5 |
| 5 | Does the test lamp remain illuminated? | Go to Step 6 | Go to Step 7 |
| 6 | Test the control circuit of the automatic transmission shift lock control solenoid for a short to battery voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | Go to Step 9 |
| 7 | Test the control circuit of the automatic transmission shift lock control solenoid for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | Go to Step 9 |
| 8 | Inspect for poor connections at the harness connector of the automatic transmission shift lock control solenoid. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | Go to Step 11 |
| 9 | Inspect for poor connections at the harness connector of the body control module (BCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | Go to Step 12 |
| 10 | Repair the open in the automatic transmission shift lock control ground circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 13 | |
| 11 | Replace the automatic transmission shift lock control solenoid. Refer to Automatic Transmission Shift Lock Actuator Replacement . Did you complete the replacement? | Go to Step 12 | |
| 12 | IMPORTANT: Perform the set up procedures for the BCM. Replace the BCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup and programming.Did you complete the replacement? | Go to Step 12 | |
| 13 | Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Does the DTC reset? | Go to Step 2 | System OK |
| IMPORTANT |
|---|
| Perform the set up procedures for the BCM. |
Shift Lever Can Be Moved without Brake Pedal Depressed
Removal Procedure
- Disconnect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (L26)»(/buick/lacrosse/i-2004-2009/remont/charging-system/#battery-charging-system-and-starting-system) or «Battery Negative Cable Disconnect/Connect Procedure (LY7)»(/buick/lacrosse/i-2004-2009/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
- Remove the center console. Refer to «Console Replacement - Front Floor»(/buick/lacrosse/i-2004-2009/remont/gauges-instrument-panels/#instrument-panel-gages-and-console) in Instrument Panel, Gages and Console.
- Disconnect the automatic transaxle shift lock actuator electrical connector (1).
- Remove both ends of the automatic transaxle shift lock actuator from the pivot points.
Installation Procedure
- Install both ends of the automatic transaxle shift lock actuator to the pivot points.
- Connect the automatic transaxle shift lock actuator electrical connector (1).
- Install the center console. Refer to «Console Replacement - Front Floor»(/buick/lacrosse/i-2004-2009/remont/gauges-instrument-panels/#instrument-panel-gages-and-console) in Instrument Panel, Gages and Console.
- Connect the negative battery cable. Refer to «Battery Negative Cable Disconnect/Connect Procedure (L26)»(/buick/lacrosse/i-2004-2009/remont/charging-system/#battery-charging-system-and-starting-system) or «Battery Negative Cable Disconnect/Connect Procedure (LY7)»(/buick/lacrosse/i-2004-2009/remont/charging-system/#battery-charging-system-and-starting-system) in Engine Electrical.
Automatic Transmission Shift Lock Control Description and Operation
The automatic transmission shift lock control system is a safety device that prevents an inadvertent shift out of PARK when the engine is running. The driver must press the brake pedal before moving the shift lever out of the PARK position. The system consists of the following components
- The automatic transmission shift lock control solenoid
- The body control module (BCM)
- The powertrain control module (PCM) if equipped with the 3.6L engine
- The transmission control module (TCM) if equipped with the 3.8L engine
The BCM controls the voltage to the shift lock control solenoid through the shift lock control solenoid controlled voltage circuit. The following conditions must be met before the BCM will supply voltage to the shift lock solenoid.
- The ignition is in the ON position.
- The PCM sends an input to the BCM indicating the transmission is in the PARK position if equipped with the 3.6L engine.
- The TCM sends an input via Class 2 serial data to the BCM indicating the transmission is in the PARK position if equipped with the 3.8L engine.
- The BCM determines the brake pedal is not applied according the brake pedal position.
Since the shift lock control solenoid is permanently grounded, the BCM supplies voltage to the automatic transmission shift lock control solenoid, mechanically locking the shift lever in the PARK position as the solenoid energizes. When the brake pedal is applied, the BCM turns the control voltage output of the shift lock control solenoid OFF, de-energizing the shift lock control solenoid. The de-energized solenoid releases the mechanical lock allowing the driver to move the shift lever out of the PARK position. When the transmission is out of the PARK position, the shift lock control solenoid remains de-energized.
During remote start operation the BCM will energize the shift lock control circuit, locking the shift lever in the PARK position.
See also:
• Splicing Twisted or Shielded Cable
• Diagnostic System Check - Vehicle
• Testing for Intermittent Conditions and Poor Connections
• Computer/Integrating Systems Connector End Views
• Circuit Testing
• Wiring Repairs
• Connector Repairs
• Control Module References
• Checking Aftermarket Accessories
• Stop Lamps Inoperative
• Battery Negative Cable Disconnect/Connect Procedure (L26)
• Console Replacement - Front Floor
• Automatic Transmission Shift Lock Control Schematics
• Automatic Transmission Shift Lock Control Connector End Views
• Automatic Transmission Shift Lock Control Description and Operation
• Shift Lever Does Not Move with Brake Pedal Depressed
• Shift Lever Can Be Moved without Brake Pedal Depressed