DESCRIPTION



This vehicle is equipped with a Steering Control Module (SCM) (4) that houses an integral, internal clockspring. On some vehicles, the SCM also includes an integral, internal Steering Angle Sensor (SAS). The SCM is secured near the top of the steering column below the steering wheel and is completely concealed beneath the steering column shrouds. The SCM is installed as a modular unit that supports the left (lighting) multi-function switch (1), the right (wiper) multi-function switch (2), the hazard switch (3) and the turn signal cancel cam. The controls for each of the switches extend through appropriate clearance holes provided in the steering column shrouds.

The microprocessor-based SCM utilizes integrated circuitry and information carried on the Controller Area Network (CAN) data bus along with several hard wired analog and multiplexed inputs to monitor both the right and left multi-function switches, the ignition switch, the horn switch, the speed control switches and the remote radio switches. In response to those inputs, the internal circuitry and programming of the SCM allow it to control and integrate many electronic functions and features of the vehicle through both hard wired outputs and the transmission of electronic message outputs to other electronic modules in the vehicle over the CAN data bus. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES/COMMUNICATION - DESCRIPTION - CAN BUS).



The SCM circuitry, the clockspring, and the SAS are all contained within a flat, round molded plastic case. The back (instrument panel side) of the case has an integral mounting bracket that is secured to the stationary steering column housing with two screws. The back of the case also features a total of five integral fixed connector receptacles. The three upper receptacles are direct interface connectors for the hazard and multi-function switches and are concealed when these switches are mounted. The two lower receptacles connect the SCM to the vehicle electrical system through two take outs and connectors of the instrument panel wire harness.

The face of the SCM case consists of the rotating clockspring rotor with two integral connector receptacles and two pigtail wires with connectors located near the top. One receptacle receives the connector from the remote radio switches, and the other receives the connector from the horn switch and the speed control switches. The two pigtail wires contain the multistage driver airbag squib circuits. The turn signal cancel cam (not shown) extends from the back of the SCM case but is secured to the hub of the clockspring rotor and is keyed to the steering shaft so that it rotates the clockspring rotor with the steering wheel rotation.

A service replacement SCM is shipped with the clockspring pre-centered and with a molded plastic locking pin installed. The locking pin secures the centered clockspring rotor to the SCM case during shipment and handling, but must be removed after the SCM is installed on the steering column and before the steering wheel is installed. (Refer to 8 - ELECTRICAL/RESTRAINTS/CLOCKSPRING - STANDARD PROCEDURE - CLOCKSPRING CENTERING). The service replacement clockspring is also shipped in a standard configuration and must be electronically configured for certain optional equipment before these features will be operational. This optional equipment includes: automatic headlamps, front fog lamps, rear fog lamps, and SAS. Using a diagnostic scan tool, follow the programming steps outlined for CONFIGURE SCM under MISCELLANEOUS FUNCTIONS for the SCM/STEERING CONTROL MODULE menu item as appropriate.

The SCM has programmable memory that can be reprogrammed using a diagnostic scan tool and Flash reprogramming procedures. The SCM cannot be adjusted or repaired. If ineffective or damaged the entire SCM including the integral clockspring and, if the vehicle is so equipped, the SAS must be replaced. The left and right multi-function switches, the hazard switch and the turn signal cancel cam can be removed from and are serviced separately from the SCM.