GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

DEFINITION: Transmission shift lever does not move out of the PARK position with the ignition ON and the brake pedal pressed.

1

Did you perform the Automatic Transmission Shift Lock Control Symptom Tests and perform the necessary inspections?

Go to Step 2

Go to Symptoms - Automatic Transmission Shift Lock Control

2

  1. Disconnect the automatic transmission shift lock control switch.
  2. Turn the ignition ON with the engine OFF.
  3. Press the brake pedal and hold.
  4. Attempt to move the shift lever out of the PARK position.

Does the shift lever move out of the PARK position?

Go to Step 5

Go to Step 3

3

  1. Leave the automatic transmission shift lock control switch disconnected.
  2. Connect a test lamp between the automatic transmission shift lock control signal circuit at the automatic transmission shift lock control solenoid and a good ground.

Does the test lamp illuminate?

Go to Step 4

Go to Step 7

4

Repair short to battery positive voltage (B+) in the automatic transmission shift lock control signal circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 9

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5

    • Inspect for proper automatic transmission shift lock control switch adjustment. Refer to Stop Lamp Switch Adjustment in Hydraulic Brakes.
    • Inspect for poor connections at the automatic transmission shift lock control switch. 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 9

Go to Step 6

6

Replace the automatic transmission shift lock control switch. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes.

Did you complete the replacement?

Go to Step 9

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7

Inspect for poor connection at 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 9

Go to Step 8

8

Replace the automatic transmission shift lock control solenoid.

Go to Step 9

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9

Operate the system in order to verify the repair.

Did you find and correct the condition?

System OK

Go to Step 2