Steering Column Control Module (SCCM)

DESCRIPTION 

Courtesy of CHRYSLER GROUP, LLC

1 - SCCM

This vehicle is equipped with a Steering Column Control Module (SCCM), which combines the following components in a single assembly to ease manufacturing complexity:

• Clockspring  - The clockspring is completely concealed beneath the shrouds at the top of the steering column, just below the steering wheel. The clockspring also includes a Steering Angle Sensor (SAS) that is secured to the back of the clockspring housing and is serviced only as a unit with the SCCM. Refer to RESTRAINT SYSTEM, DESCRIPTION AND OPERATION .
• Multifunction Switch  - The only visible component of the multifunction switch is the control stalk, which includes a control knob that extends through the shrouds on the left side of the steering column. The multifunction switch includes an integral Local Interface Network (LIN) data bus slave node. The multifunction switch is serviced only as a unit with the SCCM. Refer to WIPER SYSTEM AND WASHER SYSTEM, DESCRIPTION AND OPERATION .
• Steering Angle Sensor  - The Steering Angle Sensor (SAS) is completely concealed on the back of the clockspring housing beneath the shrouds at the top of the steering column. The SAS housing is constructed of molded black plastic and is serviced only as a unit with the SCCM. The SAS includes an integral LIN data bus master node and is also a gateway to the Controller Area Network - Chassis (CAN-C) data bus network.

OPERATION 

The SCCM in this vehicle is connected to the CAN-C data bus and has one dedicated LIN data bus 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 Driver AirBag (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 back lighting 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-C data bus.

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 WIRE SPLICING , CONNECTOR TERMINAL REMOVAL and CONNECTOR TERMINAL INSTALLATION .

However, conventional diagnostic methods will not prove conclusive in the diagnosis of the SCCM electronic components or the electronic controls and communication between modules and other devices that rely upon inputs from the SCCM components to provide some features. The most reliable, efficient and accurate means to diagnose the SCCM components or the electronic controls and communication related to SCCM component operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.

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 may be compromised. 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 .