GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

1

Did you review the Automatic Transmission Shift Lock Control Circuit Description and Automatic Transmission Shift Lock Control Description and perform the necessary inspections?

Go to Step 2

Go to Symptoms - Automatic Transmission Shift Lock Control

2

  1. Turn the ignition switch to the ON position.
  2. Attempt to move the selector lever out of the PARK position. The selector lever should not move from the PARK position.
  3. Press and hold the brake pedal.
  4. Attempt to move the selector lever out of the PARK position. The selector lever should move out of the PARK position.

Does the shift lock control operate properly?

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

Go to Step 3

3

  1. Disconnect the shift lock control module connector.
  2. Turn the ignition switch to the OFF position.
  3. Test for a short to voltage in the GRN/WHT wire at cavity 2 of the shift lock control module.

Is a short to voltage present?

Go to Step 4

Go to Step 7

4

    • Test for a short to voltage in the GRN/WHT wire between the stoplamp switch connector cavity 1 and the shift lock control module connector cavity 2.
    • Test for a short to voltage in the RED/WHT wire between the stoplamp switch connector cavity 2 and junction block 2 connector 3 cavity 7.

Is a short to voltage present?

Go to Step 5

Go to Step 6

5

Repair the short to voltage in the GRN/WHT wire or in the RED/WHT wire. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

Go to Step 8

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6

Adjust or replace the stoplamp switch. Refer to Stop Lamp Switch Adjustment or Stop Lamp Switch Replacement in Hydraulic Brakes.

Is the repair complete?

Go to Step 8

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7

Replace the shift lock control module. Refer to Shift Lock Control Module Replacement in Automatic Transmissions 3 Speed - MB3 or Shift Lock Control Module Replacement in Automatic Transmissions 4 Speed - MS7.

Is the repair complete?

Go to Step 8

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8

Operate the system in order to verify the repair.

Did you find and correct the condition?

System OK

Go to Step 3