Principles Of Operation

Steering Column

Principles of Operation


Power Adjustable Steering Column

The adjustable steering column is controlled by 2 electric motors that are powered by the Driver Seat Module (DSM). The DSM receives input from the steering column control switch. The steering column control switch is a 4-position, momentary-contact switch located on the LH side of the steering column just below the multifunction switch. When the steering column control switch is moved to any of the 4 positions, it sends a signal to the DSM to tilt the steering column up or down or telescope the steering column forward or rearward. The power tilt motor is serviceable separately from the steering column. The power telescoping motor is not serviceable. If a new telescoping motor is needed, a new steering column must be installed.

Memory Position Programming and Recall

The memory feature allows automatic positioning of the driver seat, power mirror and adjustable steering column to 2 programmable positions. An adjustable steering column position can be stored at any time using the memory position switches. A memory position can only be recalled when the vehicle's transmission selector lever is in the PARK or NEUTRAL position. A memory position can be programmed to a Remote Keyless Entry (RKE) transmitter. If a RKE transmitter is programmed to a memory position, using the RKE transmitter to unlock the vehicle will move the driver seat, power mirror and adjustable steering column to the associated memory position. Both the integrated keyhead and the intelligent access key type transmitters support this feature. For information on the DSM and the memory position feature, refer to Seating Programming and Relearning. For instruction for programming and recalling a memory position, refer to seating and safety restraints in the Owner's Literature.


Easy Entry/Exit

The easy entry/exit function moves the steering column to the full inward and upward position when the transmission selector lever is in the PARK position and the ignition is selected off (if equipped with a push button start system) or if the key-in-ignition switch indicates that the ignition key has been removed from the ignition lock cylinder (if equipped with an ignition switch). The DSM receives an ignition status message over the Medium Speed Controller Area Network (MS-CAN). When the ignition status message indicates that the ignition key has been removed from the lock cylinder (vehicles with an ignition switch), the DSM will command the steering column to the full upward/forward position. For vehicles equipped with a push button start system, this occurs when the ignition status message indicates that the ignition status transitions off. The DSM will cancel this operation if a valid input is received from the steering column control switch or memory position switch.

The DSM will record the current steering column position before powering the steering column for an easy exit operation. This recorded position will be used to return the steering column to this position on the easy entry operation. During easy entry operation, the steering column is returned to the position previous to the easy exit operation.

The easy entry/exit feature can be activated or deactivated using the message center. Refer to driver controls in the Owner's Literature for additional instructions for using the message center.


Tilt/Telescoping Motor Sensors

The DSM receives input from a Hall-effect type rotation sensor located in the power tilt motor and the power telescoping motor. The sensors provide a digital signal used by the DSM to calculate the location of the steering column in relation to the full forward/rearward and full up/down positions. The DSM uses this signal to store and recall memory positions, to perform the easy entry/exit operations and to ensure the tilt and telescoping motors will not stall against the steering column end of travel in the forward/rearward or up/down directions. The tilt motor sensor is internal to the power tilt motor. The power tilt motor is serviced separately from the steering column. The telescoping (reach) motor sensor is internal to the power telescoping motor. The power telescoping motor is not serviceable. If a new telescoping motor sensor is needed, a new steering column must be installed.


Jog Mode

If the DSM loses signal from either of the motor sensors, the steering column will operate in jog mode. Jog mode allows limited operation of the steering column using only the steering column control switch. When the steering column control switch is operated in jog mode, the steering column will move in the desired direction for one second, then stop. The steering column control switch must be released, then pressed again in order to move the steering column for an additional second. Jog mode is an indication that there is a tilt or telescoping motor sensor fault. If the adjustable steering column is operating in jog mode, a DTC will be set in the DSM.