GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Shift Lock Control Schematics

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

1

Did you perform the Symptoms - Automatic Transmission Shift Lock Control tests and all the necessary inspection?

Go to Step 2

Go to Symptoms - Automatic Transmission Shift Lock Control

2

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

Does the shift lever move out of the PARK position?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

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

Does the transmission shift lever move out of the PARK position?

Go to Step 6

Go to Step 4

4

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

Does the transmission shift lever move out of the PARK position?

Go to Step 7

Go to Step 5

5

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 10

Go to Step 9

6

Inspect for poor connections at the harness connector of 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 10

Go to Step 8

7

Repair the short to battery positive voltage in the A/T shift lock control solenoid supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 10

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8

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 10

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9

Replace the automatic transmission shift lock control solenoid. Refer to Automatic Transmission Shift Lock Actuator Replacement .

Did you complete the replacement?

Go to Step 10

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10

Operate the system in order to verify the repair.

Did you find and correct the condition?

System OK

Go to Step 2