GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The body control module (BCM) controls the automatic transmission (A/T) shift lock control solenoid ground circuit and monitors the voltage of the ground control circuit.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B2712 Gearshift Lock Circuit Low

Conditions for Running the DTC

The control ground circuit of the A/T shift lock control solenoid must be OFF.

Conditions for Setting the DTC

    • The BCM detects the controlled ground circuit voltage is approximately equal to ground in the OFF state.
    • The condition above must be present for more than 0.3 seconds.
    • This DTC will be set after 20 seconds due to possible false failures.

Action Taken When the DTC Sets

The BCM stores DTC B2712 in memory.

Conditions for Clearing the DTC

    • A current DTC B2712 will clear if the short to ground or open in the controlled ground circuit of the A/T shift lock control solenoid is no longer detected by the BCM.
    • A history DTC B2712 will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.
    • A scan tool may be used to clear the DTC.

Diagnostic Aids

    • If DTC B2712 is a history DTC, the fault may be intermittent. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
    • The following conditions may cause an intermittent malfunction to occur:
       - An intermittent short to ground or open in the controlled ground circuit of the A/T shift lock control solenoid
       - The A/T shift lock control solenoid coil is intermittently shorted to ground internally.
       - The BCM is intermittently shorted to ground internally.

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 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

  1. Turn ON the ignition, with the engine OFF.
  2. Press and hold the brake pedal.
  3. Attempt to move the gearshift lever from the PARK position.

Does the automatic transmission (A/T) shift lock control system operate correctly?

Go to Diagnostic Aids

Go to Symptoms - Automatic Transmission Shift Lock Control