LMC5 MODULE

The steering column lock system is an electromechanical theft deterrent system designed to prevent the steering wheel from turning if the proper ignition key has not been inserted.

When the car is off and locked, a pin fits into a mating hole in a column lock plate under the steering column, preventing the steering column from turning. When the correct key is inserted into the ignition, the Body Control Module (BCM), a computer module that controls a variety of vehicle functions, sends an unlock signal to the column lock motor. The motor retracts the pin from the hole in the lock plate. The motor also sends a signal back to the BCM to confirm that the pin has actually retracted.

The vehicle then operates normally. When the key is removed from the ignition, the BCM signals the lock motor to extend the pin. The pin is spring loaded, so that if it isn’t in line with a lock plate hole, the spring will push it into the hole once the steering wheel is turned by a small amount, thus locking the column.

So, the main column lock components are the lock motor, lock plate, lock pin, and associated hardware, pin location feedback switch, a relay in manual transmission models, and wires and connectors between these components, power, ground, and the BCM.

Unfortunately, the column lock system can experience various failure modes, and is also quite sensitive to low battery voltages and rapid key insertion/removal. A steering column lock system failure will almost certainly affect every C5 subject to the recall, at some time. When one of these failures occurs, the Driver Information Center will display either the dreaded Service Column Lock, or, Pull Key, Wait 10 Seconds messages, and the fuel will be cut off at 2MPH.

 The manufacturer has issued four recalls, which have corrected the problems to varying degrees, but which can also fail in new and completely different ways. The recalls variously disabled the locking pin and motor, performed reprogramming, or added various other components in an attempt to fix the problem.

To determine if at least the first recall has been done and your steering wheel is unlocked