GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Shift Lock Control Schematics

Connector End View Reference: Body Control System Connector End Views in Body Control System

DEFINITION: Transmission shift lever will not moved out of the PARK position with the Ignition on and the brake pedal pressed.

1

Did you perform the Diagnostic System Check - Automatic Transmission Shift Lock Control?

Go to Step 2

Go to Diagnostic System Check - 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. Install a scan tool.
  3. Turn ON the ignition, with the engine OFF.
  4. Press and hold the brake pedal.
  5. With the scan tool, turn the brake to shift relay output control ON in the body control module (BCM) output control data list.
  6. Attempt to move the shift lever out of the PARK position.

Does the shift lever move out of the PARK position?

Go to Step 4

Go to Step 6

4

  1. With the scan tool, observe the brake switch input in the body control module (BCM) data display list.
  2. Press and release the brake pedal several times while observing the scan tool.

Does the brake input display ON and OFF with the brake pedal operation?

Go to Step 5

Go to Diagnostic Starting Point - Lighting Systems in Lighting Systems

5

With the scan tool observe the gear position parameter in the powertrain control module (PCM) data list.

Does the scan tool indicate PARK position?

Go to Step 10

Go to Diagnostic System Check - Engine Controls in Engine Controls -- 2.2L (L61)

6

  1. Turn OFF the ignition.
  2. Connect a test lamp between the automatic transmission shift lock control solenoid control circuit and a good ground.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, command the shift lock control relay output ON in the BCM output control data list.

Does the test lamp illuminate?

Go to Step 7

Go to Step 8

7

Test the shift lock control solenoid ground circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 13

Go to Step 9

8

Test the automatic transmission shift lock control circuit for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring System.

Did you find and correct the condition?

Go to Step 13

Go to Step 10

9

Inspect for poor connections as 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 13

Go to Step 11

10

Inspect for poor connections as 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 13

Go to Step 12

11

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

Did you complete the replacement?

Go to Step 13

--

12

Replace the body control module (BCM). Refer to Body Control Module Replacement in Body Control System.

Did you complete the replacement?

Go to Step 13

--

13

Operate the system in order to verify the repair.

Did you find and correct the condition?

System OK

Go to Step 3