The BCM provides the steering column control function which allows the column to be electronically locked or unlocked. The BCM provides two outputs, column lock drive (A) and column unlock drive (B). The BCM can apply a ground or battery output on the column lock drive (A) CKT 1603 or column lock drive (B) CKT 1604 depending on the desired steering column lock motor position. The BCM accomplishes steering column lock motor operation based on the following output commands:

The BCM controls the position of the steering column lock motor based on the following input information:

The BCM supplies the ground to the steering column motor 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 BCM 2 fuse #23. The BCM uses a feedback switch which is integrated within the steering column lock motor in order to monitor the motor position. The feed back 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 fuse #25 for 15 seconds. The BCM also monitors its circuitry for the column lock/unlock drive (A) circuit. If the BCM detects a malfunction present 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.