GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

1

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

Go to Step 2

Go to Symptoms - Automatic Transmission Shift Lock Control

2

  1. Place the manual selector in Park.
  2. Turn the ignition switch ON.
  3. Depress the brake pedal.

Does the shift lock control operate?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

  1. Place the manual selector in Park.
  2. Turn the ignition switch ON.
  3. Depress the brake pedal.
  4. Test for battery voltage at terminal 2 of the stoplamp switch. Refer to Circuit Testing in Wiring Systems.

Is battery voltage present?

Go to Step 11

Go to Step 4

4

Test for battery voltage at terminal 4 of the stoplamp switch. Refer to Circuit Testing in Wiring Systems.

Is battery voltage present?

Go to Step 5

Go to Step 6

5

Replace or adjust the stoplamp switch. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes.

Is the repair complete?

Go to Step 16

--

6

Test for battery voltage at terminal 9 of the transaxle range switch. Refer to Circuit Testing in Wiring Systems.

Is battery voltage present?

Go to Step 7

Go to Step 8

7

Repair the open in the ORN/BLK wire between the transaxle range switch and the stoplamp switch. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

Go to Step 16

--

8

Test for battery voltage at terminal 8 of the transaxle range switch. Refer to Circuit Testing in Wiring Systems.

Is battery voltage present?

Go to Step 9

Go to Step 10

9

Replace the transaxle range switch. Refer to Transaxle Range Switch .

Is the repair complete?

Go to Step 16

--

10

Repair the open in the YEL wire between the transaxle range switch and the junction block. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

Go to Step 16

--

11

  1. Place the manual selector in Park.
  2. Turn the ignition switch ON.
  3. Depress the brake pedal.
  4. Test for battery voltage at terminal 4 of the shift lock solenoid connector. Refer to Circuit Testing in Wiring Systems.

Is battery voltage present?

Go to Step 13

Go to Step 12

12

Repair the open in the ORN/WHT wire between the stoplamp switch and the shift lock solenoid. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

Go to Step 16

--

13

Test for an open in the BLK wire between the shift lock solenoid connector and G400. Refer to Circuit Testing in Wiring Systems.

Is an open present?

Go to Step 14

Go to Step 15

14

Repair the open in the BLK wire between the shift lock solenoid and G400. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

Go to Step 16

--

15

Replace the shift lock solenoid. Refer to Brake Transmission Shift Interlock .

Is the repair complete?

Go to Step 16

--

16

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3