GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Shift Lock Control Schematics

Connector End View Reference: Shift Lock Control Connector End Views or Keyless Entry Connector End Views

DEFINITION: Transmission shift lever does not lock in the PARK position with the ignition ON and the brake pedal not depressed.

1

Did you perform the A Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Apply the parking brake and block the wheels.
  2. Turn ON the ignition, with the engine OFF.
  3. Attempt to move the shift lever out of the PARK position without pressing the brake pedal.

Does the shift lever move out of the PARK position?

Go to Step 3

Go to Testing for Intermittent Conditions and Poor Connections

3

  1. Turn OFF the ignition.
  2. Install a scan tool.
  3. Turn ON the ignition, with the engine OFF.
  4. Ensure brake pedal is released.
  5. With a scan tool, observe the shift lock control output in the remote control door lock receiver (RCDLR) data list.

Does the scan tool display an Active status?

Go to Step 4

Go to Step 5

4

With a scan tool, observe the brake switch input in the transmission control module (TCM) data list.

Does the brake switch status indicate Inactive?

Go to Step 8

Go to Stop Lamps Always On

5

  1. Turn OFF the ignition.
  2. Disconnect the electrical connector of the shift lock control solenoid.
  3. Apply the parking brake and block the wheels.
  4. Turn ON the ignition, with the engine OFF.
  5. Attempt to move the shift lever out of the PARK position.

Does the shift lever move out of the park position?

Go to Step 7

Go to Step 6

6

Test the shift lock control solenoid control circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 11

Go to Step 8

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 .

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 RCDLR. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 11

Go to Step 10

9

Replace the automatic transmission shift lock control . Refer to Transmission Control Replacement .

Did you complete the replacement?

Go to Step 11

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10

Replace the RCDLR. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 11

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11

Operate the system in order to verify the repair.

Did you find and correct the condition?

System OK

Go to Step 2