GM Service Manual Online
For 1990-2009 cars only

Column Lock Functional State (Ignition ON)

Symptoms

Possible Malfunctions

Use a scan tool to display the steering column lock state. Turn ON the ignition switch, and select BCM data display (Column Lock State).

Enable Stdby

(Requires battery disconnect to clear)

    • SERVICE COLUMN LOCK message
    • Engine Cranks, No Start
    • Column won't LOCK or UNLOCK
    • Column lock motor disconnected with ign ON.
    • Open or shorted column lock feedback switch.
    • Open or shorted column lock feedback circuit (with ignition ON).

Unlocking Failure

    • SERVICE COLUMN LOCK Message
    • PULL KEY-WAIT 10 SEC message
    • PCM disables fuel
    • Column won't LOCK or UNLOCK
    • Steering column motor Malfunction
    • Open or shorted steering column motor circuit
    • Open or shorted Steering column lock relay circuit
    • SERVICE COLUMN LOCK Message
    • PULL KEY-WAIT 10 SEC message
    • PCM disables fuel
    • Open or shorted column lock feedback switch.
    • Open or shorted column lock feedback circuit

Lock Failure

    • SERVICE COLUMN LOCK message
    • PULL KEY-WAIT 10 SEC message
    • PCM disables fuel
    • Column won't LOCK or UNLOCK
    • Steering column motor Malfunction
    • Open or shorted steering column motor drive circuit
    • Open or shorted Steering column lock relay circuit

Unlk Volt Delay

    • Steering column won't UNLOCK
    • PCM disables fuel
    • Abnormal Steering column motor sounds

Low battery voltage

Lock Fail Unlk

After 1 second enters Lock Fail Standby state

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Lock Fail Stdby

    • SERVICE COLUMN LOCK message
    • PULL KEY-WAIT 10 SEC message
    • PCM disables fuel
    • Column won't LOCK or UNLOCK
    • Steering column motor Malfunction
    • Open or shorted steering column motor drive circuit
    • Battery disconnected with the key IN the ignition
    • Feedback circuit malfunction
    • Open fuse #23
    • Open or shorted Steering column lock relay circuit

Enable Unlk

After 1 second enters Lock Fail Standby state

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PCM F.E Latch

    • Column won't LOCK
    • Unable to communicate with the PCM
    • BCM stores a DTC U1016 and/or DTC U1255
    • Loss of communications between the BCM and PCM
    • Serial data line open or short

PCM F.E Stdby

    • Column won't LOCK
    • Unable to communicate with the PCM
    • BCM stores a DTC U1016 and/or DTC U1255
    • Loss of communications between the BCM and PCM
    • Serial data line open or short

PCM F.E Unlock

After 1 second enters PCM Fail Enable Standby state

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