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.
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 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. |
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.
Tests for battery voltage at the control circuit of the A/T shift lock control solenoid.
Tests for an open or short to ground at the control circuit of the A/T shift lock control solenoid.
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 or Computer/Integrating Systems Connector End Views | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |
Does the 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 body control module (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 Transmission Control 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 |