GM Service Manual Online
For 1990-2009 cars only

Diagnostic Aids

    • An open on the key in ignition switch signal circuit will intermittently cause the column not to unlock.
    • Disconnecting or opening the steering column lock feedback circuit will cause the BCM to enter a Fail Enable Standby mode. The steering column will remain inoperative until the Fail Enable Standby mode is cleared. To clear this mode, disconnect the BCM1 & IPC fuse in the I/P fuse block for 15 seconds.

Step

Action

Yes

No

Schematic Reference: Column/Ignition Lock Schematics

Connector End View Reference: Steering Wheel and Column Connector End Views

1

Did you perform the Steering Wheel and Column Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Steering Wheel and Column

2

Verify the fault is present.

Does the system operate normally?

Go to Diagnostic Aids

Go to Step 3

3

  1. Disconnect the BCM1 & IPC fuse in the I/P fuse block for 15 seconds.
  2. Reconnect the BCM1 & IPC fuse.

Does the steering column lock unlock and lock normally?

Go to Step 11

Go to Step 4

4

Verify that the column will lock or unlock by cycling the ignition on and removing the ignition key.

Does the steering column lock unlock and lock normally?

Go to Step 5

Go to Electronic Column Lock Does Not Unlock or Electronic Column Lock Does Not Lock .

5

With a DMM, back probe between steering column lock signal circuit on the BCM and a good ground.

Is battery voltage present?

Go to Step 6

Go to Step 8

6

Test the signal and ground circuits of the steering column lock feedback switch for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 7

7

Inspect for poor connections at the harness connector of the steering column lock. 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 11

Go to Step 9

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 11

Go to Step 10

9

Replace the steering column lock. Refer to Steering Wheel Theft Deterrent Lock Replacement in Steering Wheel and Column.

Did you complete the replacement?

Go to Step 11

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10

Important: Perform the BCM RPO Reprogram procedure. Refer to Body Control Module (BCM) Programming/RPO Configuration in Body Control System.

Replace the BCM. Refer to Body Control Module Replacement in Body Control System.

Did you complete the replacement?

Go to Step 11

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11

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3