Description And Operation: Operation

The SCCM in this vehicle does not have any connection to the Control Area Network (CAN) and instead has two dedicated Local Interface Network (LIN) data buses used by the steering wheel switches for transmission of resistor multiplexed momentary signals to the Body Control Module (BCM). All other circuits used by the steering wheel components are hard wire pass-through circuits. The circuits for the horn switch, the optional heated steering wheel and the standard equipment DAB are pass-through circuits of the SCCM.

The switch pods (if equipped) in the left and right horizontal spokes of the steering wheel are each LIN bus slave nodes. The switch states of the hands-free communication switches and the Electronic Vehicle Information Center (EVIC) control switches in the left switch pod are communicated over the LIN bus directly to the LIN bus master node of the BCM. The left switch pod also controls the backlighting of both switch pods. The switch states of the speed control switches in the right switch pod are communicated over the LIN bus to the LIN master node of the BCM. The internal circuitry of the BCM gateway then relays electronic message outputs communicating those switch states, turn signal and wiper stalk data to other electronic modules in the vehicle over the CAN-C bus.

Four fixed connector receptacles on the SCCM connect to the instrument panel wire harness via four wiring harness connectors.

The SCCM is connected to a fused B(+) circuit and receives a path to ground at all times. These connections allow it to remain functional regardless of the ignition switch status. Any input to the SCCM that controls a vehicle system function that does not require that the ignition switch status be ON such as pressing the horn switch, prompts the BCM to wake up and transmit on the CAN data bus.

The service replacement SCCM is shipped with the clockspring centered within the SCCM and with a plastic locking tab installed. This locking tab should not be removed until the SCCM has been properly installed on the steering column. If the locking tab is removed before the steering wheel is installed on a steering column, clockspring centering must be confirmed by viewing the inspection window on the clockspring rotor. If the clockspring centering is compromised, the entire SCCM must be replaced with a new unit. Refer to MODULE, STEERING COLUMN CONTROL (SCCM), REMOVAL AND INSTALLATION .

The hardwired circuits between components related to the SCCM may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. The wiring information includes wiring diagrams, details of wire harness routing and retention, connector pin-out information and location views for the various wire harness connectors, splices and grounds. For proper wire repair, and connector repair procedures. Refer to STANDARD PROCEDURE and REMOVAL or INSTALLATION .