GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Saturn 🢒 2005 🢒 L300/LW300 🢒 Brakes 🢒 Park Brake 🢒 DTC B2707

Object Number: 1473147 Size: MF

Circuit Description

The body control module (BCM) controls the automatic transmission shift lock control solenoid by providing a controlled ground to the automatic transmission shift lock control solenoid. The BCM utilizes a smart driver to monitor the voltage and current flow of the automatic transmission shift lock control solenoid control circuit. DTC B2707 will set when the BCM detects a short to ground when the solenoid is in the OFF state.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B2707 Gearshift Unlock Circuit Low

Conditions for Running the DTC
    • The ignition switch is in the ON position.
    • The brake pedal is released.
    • The transmission the PARK position.

Conditions for Setting the DTC

The BCM detects the shift lock control solenoid control circuit is grounded for a minimum of 1 second.

Action Taken When the DTC Sets

The BCM disables shift lock control solenoid operation until the next key cycle.

Conditions for Clearing the DTC
    • A current DTC B2707 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
    • If the automatic transmission (A/T) shift lock control circuit is shorted to ground , the A/T shift lock control solenoid will be energized. The shift lever will not shift out of PARK position with the brake pedal pressed.
    • 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 in Wiring Systems.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. 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.

    2.

  2. Tests for ground at the control circuit of the automatic transmission shift lock control solenoid.

Step

Action

Yes

No

Schematic Reference: Shift Lock Control Schematics

Connector End View Reference: 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. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, command the shifter unlock solenoid output control parameter 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
  1. Turn OFF the ignition.
  2. Connect a test lamp between the automatic transmission shift lock control solenoid voltage supply circuit at the connector of the automatic transmission shift lock control solenoid connector and a good ground.
  3. Turn ON the ignition, with the engine OFF.

Does the test lamp illuminate?

Go to Step 4

Go to Step 8

4

  1. Turn OFF the ignition.
  2. Disconnect the automatic transmission shift lock control solenoid.
  3. Connect a test lamp between the shift lock solenoid control circuit at the connector of the automatic transmission shift lock solenoid and battery positive voltage.
  4. Turn ON the ignition, with the engine OFF.
  5. With a scan tool, command the shifter unlock solenoid output control ON and OFF several times.

Does the test lamp illuminate ON and OFF with each command?

Go to Step 6

Go to Step 5

5

Test the control circuit of the automatic transmission shift lock control solenoid for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 7

6

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

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 11

Go to Step 10

8

Repair the open or short to ground in the automatic transmission shift lock control solenoid voltage supply circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 11

--

9

Replace the automatic transmission shift lock control solenoid. Refer to Shift Lock Control Solenoid Replacement .

Did you complete the replacement?

Go to Step 11

--

10

Important: Perform the set-up 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
  1. Use the scan tool in order to clear the DTCs .
  2. 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