GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

DEFINITION: The lock system will not allow the key to be turned to the OFF lock position.

1

Did you review the ignition lock system description and perform the necessary inspections?

Go to Step 2

Go to Steering Wheel and Column Description and Operation

2

Verify that the lock system does not lock.

Does the lock system operate normally?

System OK

Go to Step 3

3

Inspect for an incorrect, worn, or damaged key.

Is the key incorrect, worn, or damaged?

Go to Step 9

Go to Step 4

4

Inspect for a faulty lock cylinder.

Is the lock cylinder or release button damaged?

Go to Step 10

Go to Step 5

5

Inspect the shift linkage adjustment.

Is the shift linkage adjusted incorrectly?

Go to Step 11

Go to Step 6

6

Inspect the automatic transmission shift lock control for damage.

Is the automatic shift lock control damaged?

Go to Step 12

Go to Step 7

7

Inspect the ignition switch for damage.

Is the ignition switch damaged?

Go to Step 13

Go to Step 8

8

Inspect the park lock for damage and cycle manual override.

Is the park lock damaged?

Go to Step 14

Go to Step 3

9

Replace the key. Refer to Key and Lock Cylinder Coding in General Information.

Did you complete the repair?

Go to Step 15

--

10

Replace the lock cylinder. Refer to Ignition Lock Cylinder Replacement .

Did you complete the repair?

Go to Step 15

--

11

Adjust the shift linkage.

Did you complete the repair?

Go to Step 15

--

12

Replace the automatic transmission shift lock control.

Did you complete the repair?

Go to Step 15

--

13

Replace the ignition switch. Refer to Ignition and Start Switch Replacement .

Did you complete the repair?

Go to Step 15

--

14

Replace the park lock. Refer to Park Pawl Actuator Replacement .

Did you complete the repair?

Go to Step 15

--

15

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3