Scheme 64
Scheme 65
| Callout | Component Name |
|---|---|
| 1 | Floor Shift Light |
| 2 | Floor Pan |
| 3 | A/T Shift Lock Control Solenoid (MN5) |
| 4 | Inflatable Restraint Sensing and Diagnostic Module (SDM) |
| 5 | G306 |
| 6 | Park Brake Switch |
| 7 | G301 |
Automatic Transmission Shift Lock Control Connector End Views
A/T Shift Lock Control Solenoid Connector Part Information OEM: 12047785 Service: See Catalog 4-Way F Metri-Pack 150 Series (BK) Pin Wire Color Circuit No. Function A GY 8 Instrument Panel Lamp Supply Voltage (1) B D-GN/WH 1135 Brake Transmission Shift Interlock Solenoid Supply Voltage C D-GN/WH 1932 Shift Select Switch Park Signal D BK 1250 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 |
|---|---|---|
| Brake to Shift Control | Special Functions-Output Control | Command supplies battery voltage to the A/T shift lock control circuit ON or OFF. |
Body Control Module (BCM)
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 Voltage Signal | BCM Data | 0-15 volts | 14 volts |
| BTSI Solenoid | BCM Data | ON/OFF | ON |
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. | |||
| Ignition 1 Signal | ECM/PCM | Volts | 12 Volts |
| Stoplamp Pedal Switch | ABS, ECM/PCM | Applied/Released | Applied |
| 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 | Transmission Data | ON/OFF | OFF |
Engine Control Module (ECM) / Powertrain Control Module (PCM)
Circuit 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.
DTC Descriptor
This diagnostic procedure supports the following DTC
DTC B2705 Gearshift Unlock Circuit
This vehicle has DTCs which include DTC Symptoms. For more information on DTC Symptoms, refer to DTC Symptom Description in Vehicle DTC Information.
| DTC Symptom | DTC Symptom Descriptor |
|---|---|
| 02 | Short to Ground |
| 05 | Short to Battery or Open |
DTC B2705
Conditions for Running the DTC
- The ignition switch is in the ON position.
- The brake pedal is pressed.
- The transmission is in the PARK position.
B2705 02
Sets if there is a short to ground in the automatic transmission shift lock control solenoid control circuit.
B2705 05
Sets if there is an open or short to voltage 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.
- The BCM stores DTC B2705 in memory.
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.
- A scan tool may be used to clear the DTC.
Diagnostic Aids
- If the automatic transmission shift lock control circuit is shorted to ground, the automatic transmission shift lock control solenoid will be inoperative. The vehicle will shift out of PARK without pressing 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»(/chevrolet/cobalt/i-2004-2010/remont/electrical-component-locations/#wiring-systems-electrical-power-management__testing-for-intermittent-conditions-and-poor) in Wiring Systems.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
- 2: Listen for an audible click when the automatic transmission shift lock control solenoid operates. Command both the ON and OFF states. Repeat the commands as necessary.
- 3: This step tests for a good ground at the ground circuit of the automatic transmission shift lock control solenoid.
- 4: This step verifies that the BCM is providing battery voltage to the automatic transmission shift lock control solenoid.
- 5: This step tests if battery voltage is constantly being applied to the automatic transmission 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 | |||
| 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. 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 Shift Control Replacement in Automatic Transaxle-4T40-E/4T45-E. Did you complete the replacement? | Go to Step 13 | |
| 12 | IMPORTANT: Perform the setup procedure 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 13 | |
| 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 setup procedure 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»(/chevrolet/cobalt/i-2004-2010/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»(/chevrolet/cobalt/i-2004-2010/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»(/chevrolet/cobalt/i-2004-2010/remont/electrical-component-locations/#wiring-systems-electrical-power-management__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»(/chevrolet/cobalt/i-2004-2010/remont/automatic-trans/#shift-interlock-system__shift-lever-does-not-move-with)
- «Shift Lever Can Be Moved without Brake Pedal Depressed»(/chevrolet/cobalt/i-2004-2010/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 a 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 to Shift Control Replacement in Automatic Transaxle - 4T40-E/4T45-E. Did you complete the replacement? | Go to Step 11 | |
| 10 | IMPORTANT: Perform the setup procedure 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 setup procedure 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 Shift Control Replacement in Automatic Transaxle-4T40-E/4T45-E. Did you complete the replacement? | Go to Step 13 | |
| 12 | IMPORTANT: Perform the setup procedure 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 13 | |
| 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 setup procedure for the BCM. |
Shift Lever Can Be Moved without Brake Pedal Depressed
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 thew following components
- The automatic transmission shift lock control solenoid
- The body control module (BCM)
- The transmission control module (TCM)
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 control solenoid
- The ignition is in the ON position
- The TCM sends an input via GMLAN serial data to the BCM indicating the transmission is in the PARK position
- The BCM receives a brake applied input from the brake light switch
Since the shift lock control solenoid is permanently grounded, the BCM supplies voltage to the automatic transmission shift lock control solenoid, releasing the mechanical lock on the shift lever as the solenoid energizes. The energized solenoid allows the driver to move the shift lever out of the PARK position. When the brake pedal is not applied, the BCM turns the control voltage output of the shift lock control solenoid OFF, de-energizing the shift lock control solenoid. When the transmission is in the PARK position, the de-energized shift lock control solenoid will prevent shifting as the lever is mechanically locked in the PARK position.
See also:
• Diagnostic System Check - Vehicle
• DTC Symptom Description
• Testing for Intermittent Conditions and Poor Connections
• Circuit Testing
• Wiring Repairs
• Connector Repairs
• Shift Control Replacement
• Control Module References
• Checking Aftermarket Accessories
• Stop Lamps Inoperative
• 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