GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Column/Ignition Lock Schematics

1

Did you review the park lock operation and perform the necessary inspections?

Go to Step 2

Go to Symptoms - Steering Wheel and Column - Tilt

2

Verify the fault is present.

Does the system operate normally?

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

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Disconnect the ignition lock solenoid.
  3. Turn ON the ignition, with the engine OFF.
  4. Connect a test lamp between the battery positive voltage and ground circuits of the ignition lock solenoid.
  5. Cycle the gear shift from Park to Drive.

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

Go to Step 11

Go to Step 4

4

Connect a test lamp between the ground circuit of the ignition lock solenoid and B+ voltage.

Does the test lamp illuminate?

Go to Step 5

Go to Step 7

5

  1. Turn OFF the ignition.
  2. Reconnect the ignition lock solenoid.
  3. Disconnect the floor shift control connector.
  4. Turn ON the ignition, with the engine OFF.
  5. Connect a test lamp between the battery positive voltage and ground circuits of the park switch.

Does the test lamp illuminate?

Go to Step 10

Go to Step 6

6

Connect a test lamp between battery positive circuit of the park switch and a good ground.

Does the test lamp illuminate?

Go to Step 9

Go to Step 8

7

Repair the open in the ground circuit of the ignition lock solenoid circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 14

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8

Repair the open or short to ground of the park switch battery positive voltage circuit. Refer to Wiring Repairs .

Did you complete the repair?

Go to Step 14

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9

Repair the open, short to ground, or short to voltage of the park switch signal circuit. Refer to Wiring Repairs .

Did you complete the repair?

Go to Step 14

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10

Inspect for poor connections at the park switch. 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 14

Go to Step 12

11

Inspect for poor connections at the ignition lock 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 14

Go to Step 13

12

Replace the park switch. Refer to Transmission Control Replacement .

Did you complete the replacement?

Go to Step 14

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13

Replace the ignition lock solenoid. Refer to Electric Park Lock Module - Disassemble - Off Vehicle and Electric Park Lock Module - Assemble - Off Vehicle .

Did you complete the replacement?

Go to Step 14

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14

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3