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 Computer/Integrating Systems Connector End Views in Computer/Integrating Systems

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 Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

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 in Wiring Systems

3

  1. Turn OFF the ignition.
  2. Install a scan tool.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the BTSI output in the body control module (BCM) data list.

Does the scan tool display an ON status?

Go to Step 4

Go to Step 8

4

  1. Turn OFF the ignition.
  2. Connect a test lamp between the ignition 1 voltage circuit at the automatic transmission shift lock control solenoid and a good ground.
  3. Turn ON the ignition, with the engine OFF.

Does the test lamp illuminate?

Go to Step 5

Go to Step 9

5

  1. Turn OFF the ignition.
  2. Disconnect the automatic transmission shift lock control solenoid.
  3. Connect a test lamp between the ignition 1 voltage circuit and the automatic transmission (A/T) shift lock control circuit at the automatic transmission shift lock control solenoid connector.
  4. Turn ON the ignition, with the engine OFF.
  5. With a scan tool, command the brake to shift relay ON and OFF several times.

Does the test lamp turn ON and OFF with each command?

Go to Step 7

Go to Step 6

6

Test the A/T shift lock control circuit of an open or short to battery positive voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 12

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 in Wiring Systems.

Did you find and correct the condition?

Go to Step 12

Go to Step 10

8

Inspect for poor connections at the harness connector of the 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 12

Go to Step 11

9

Repair the open in the automatic transmission shift lock control solenoid ignition 1 voltage circuit. Refer to Circuit Testing or Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 12

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10

Replace the automatic transmission shift lock control solenoid. Refer to Transmission Control Replacement in Automatic Transaxle-4T40-E/4T45-E.

Did you complete the replacement?

Go to Step 12

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11

Important: Perform the set-up procedure for the BCM.

Replace the BCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 12

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12

Operate the system in order to verify the repair.

Did you find and correct the condition?

System OK

Go to Step 2