Steering Column Lock Operation

The BCM supplies the ground to the steering column unlock circuit through the key out of ignition switch which is integrated within the ignition switch. This prevents the BCM from locking the steering column with the key in the ignition. The BCM supplies battery voltage to the steering column lock motor through BCM2 fuse. The BCM also controls the external steering column lock relay. The relay prevents the motor from operating unless the relay is energized. The BCM uses a feedback switch which is integrated within the steering column lock motor in order to monitor the motor position. The feedback switch allows the BCM to determine if the commanded position was actually accomplished. If the BCM is unable to determine the steering column lock state, due to a steering column lock system malfunction or by disconnecting the steering column motor with the ignition in the ON position, the BCM will enter a fail enable mode and prevent steering column lock operation. The PCM will also inhibit vehicle motion by disabling fuel. To clear the BCM fail enable mode, disconnect the BCM & IPC fuse in the I/P fuse block for 15 seconds. The BCM also monitors its circuitry for the column lock circuit. If the BCM detects a malfunction present the Driver Information Center (DIC) will display PULL KEY-WAIT 10 SEC. When the key is pulled out of the ignition for 10 seconds and then key is turned to the ON position the DIC will display SERVICE COLUMN LOCK and a DTC will set in the BCM memory. Always perform the BCM Diagnostic System Check before attempting any diagnosis on the steering column lock system.