Steering Column

Steering Column

Principles of Operation

Power Adjustable Tilt/Telescope Steering Column

The power adjustable tilt/telescope steering column is controlled by the steering column control switch and 2 electric motors that are powered by the Steering Column Control Module (SCCM). The steering column control switch is a 4-position, momentary-contact switch. When the steering column control switch is moved to any of the 4 positions, it sends a signal to the SCCM (Steering Column Control Module) to tilt the steering column up or down or telescope the steering column forward or rearward.

The SCCM (Steering Column Control Module) continuously monitors the steering column tilt and telescoping motors and circuits for faults. If a fault is detected, the SCCM (Steering Column Control Module) is capable of setting DTCs.

Tilt/Telescoping Motor Sensors

The SCCM (Steering Column Control Module) receives digital signals from Hall-effect type rotation sensors that are integral to the tilt and telescoping motors. The SCCM (Steering Column Control Module) uses these signals to calculate the location of the steering column in relation to the full forward/rearward and full up/down positions. The SCCM (Steering Column Control Module) also uses these signals to store and recall memory positions, carry out the easy entry/exit operations and to make sure the tilt and telescoping motors do not stall against the steering column end of travel in the forward/rearward or up/down directions. Both the tilt and telescopic motors can be serviced separately from the steering column.

Jog Mode

If the SCCM (Steering Column Control Module) loses the signal from either of the motor sensors, the affected steering column motor operates in jog mode. Jog mode allows limited operation of the affected steering column motor using only the steering column control switch. When the steering column control switch is operated in jog mode, the steering column moves in the desired direction for one second, then stops. 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 can set in the SCCM (Steering Column Control Module).

Memory Position Programming and Recall

The SCCM (Steering Column Control Module) monitors steering column position using Hall-effect sensors that are integral to the tilt and telescoping motors. When a memory position is recalled through either the memory SET switch or the Remote Keyless Entry (RKE) transmitter, the SCCM (Steering Column Control Module) monitors the Hall-effect sensors and stops sending voltage to the steering column motors once the commanded memory position is reached. If the SCCM (Steering Column Control Module) receives a steering column switch input during a memory position recall function, the module stops the memory recall and responds to the new steering column switch position input.

When the RKE (Remote Keyless Entry) transmitter is activated, a message is sent over the Medium Speed Controller Area Network (MS-CAN) to the Driver Seat Module (DSM). When the memory SET switch is pressed, the DSM (Driver Seat Module) senses continuity to ground on the switch circuit. When the DSM (Driver Seat Module) receives either the MS-CAN (Medium Speed Controller Area Network) message or the ground input through the switch circuit, it sends a message over the MS-CAN (Medium Speed Controller Area Network) to the Body Control Module (BCM). The BCM (Body Control Module) acts as a gateway module, relaying the MS-CAN (Medium Speed Controller Area Network) message that was received from the DSM (Driver Seat Module) to the SCCM (Steering Column Control Module) over the High Speed Controller Area Network (HS-CAN). The SCCM (Steering Column Control Module) then sends voltage over the appropriate circuit to the steering column tilt or telescoping motor to adjust the steering column position.

For information on setting and recalling a memory position, refer to the Owner's Literature or Memory Position Programming in Seats.

Easy Entry/Exit

The easy entry/exit function moves the steering column to the full inward and upward position when the selector lever is in the PARK position and the ignition switch indicates the ignition key has been removed from the ignition lock cylinder. The SCCM (Steering Column Control Module) receives an ignition status message over the High Speed Controller Area Network (HS-CAN). When the ignition status message indicates the ignition key has been removed from the lock cylinder, the SCCM (Steering Column Control Module) commands the steering column to the full upward/forward position. The SCCM (Steering Column Control Module) cancels this operation if a valid input is received from the steering column control switch or memory position switch.

The SCCM (Steering Column Control Module) records the current steering column position before powering the steering column for an easy exit operation. This recorded position returns the steering column to this position on the next 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.

Power Tilt Steering Column Hard Stop/Soft Stop

A hard stop occurs when the power column physically reaches the end of travel and cannot go any further. A soft stop occurs when the power column stops before physically reaching the end of travel. The hard stop is set by steering column design and cannot be changed or adjusted. The soft stop is set by the SCCM (Steering Column Control Module). To prevent unnecessary stress on the power column and motors, the SCCM (Steering Column Control Module) sets 4 soft stop positions, one for tilt up, one for tilt down, one for telescope out and one for telescope in. The SCCM (Steering Column Control Module) uses a preset distance from the hard stop to determine where the soft stop occurs.

The soft stops must be relearned by the SCCM (Steering Column Control Module) whenever a new steering column or SCCM (Steering Column Control Module) is installed.