The body control module (BCM) controls the automatic transmission (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.
This diagnostic procedure supports the following DTC:
DTC B2705 Gearshift Unlock Circuit
• | The ignition switch is in the ON position. |
• | The brake pedal is depressed. |
• | The transmission the PARK position. |
The BCM output driver detects an open or short in the output control circuit.
The BCM disables the output control until the next ignition cycle.
• | 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. |
• | 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 A/T shift lock control circuit is shorted to battery positive voltage, the A/T 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 . |
The numbers below refer to the step numbers on the diagnostic table.
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.
This step tests for battery voltage at the control circuit of the A/T shift lock control solenoid.
This step tests for an open or short to ground at the control circuit of the A/T shift lock control solenoid.
This step tests for an open at the ground circuit of the A/T shift lock control solenoid.
Step | Action | Yes | No |
---|---|---|---|
Schematic Reference: Shift Lock Control Schematics Connector End View Reference: Shift Lock Control Connector End Views | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |
Does the automatic transmission (A/T) shift lock control solenoid turn ON and OFF with each command? | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 3 | |
Does the test lamp illuminate ON and OFF with each command? | Go to Step 5 | Go to Step 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 . Did you find and correct the condition? | Go to Step 10 | Go to Step 7 | |
Test the A/T shift lock control solenoid ground circuit for an open. Refer to Circuit Testing and Wiring Repairs . 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 . 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 BCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . 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 to Automatic Transmission Shift Lock Control 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 for replacement, setup, and programming. Did you complete the replacement? | Go to Step 10 | -- |
10 |
Does the DTC reset? | Go to Step 2 | System OK |