Restraint Control Module (RCM)

WARNING: This page is about a different car, the 2006 Mercury Mariner and 2006 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.

The RCM is on the international standards organization (ISO) 9141 communication network. The RCM controls the deployment of the air bags based on sensor input. The ISO 9141 communication network does not function if the wire is shorted to ground or battery voltage. Check the network circuit between the RCM C2041a and the DLC C251. Total resistance value must not be more than 5 ohms. If the resistance is more than 5 ohms, there is an open circuit in the ISO 9141 communication network, damage to the DLC C251, damage to the RCM C2041a, or a problem in the in-line connector. For additional information, refer to SUPPLEMENTAL RESTRAINT SYSTEM .

Power Steering Control Module

The electric power steering control module provides control of the power steering assist to the driver by replacing the conventional hydraulic valve system with an electric motor coupled to the steering gear. The motor is controlled by an electronic control unit that senses the driver's steering effort through the use of a torque sensor. Steering assist is provided in proportion to the driver's steering effort and vehicle speed. The vehicle speed signal, which is sent by the high speed CAN from the TCM, provides the necessary vehicle speed information to the power steering control module required to vary the amount or level of driver assist.

The power steering control module provides a periodic high speed CAN message that details the operating condition of the power steering system. The high speed CAN message Power Steering Malfunction is issued every 50 milliseconds. Upon receiving an indication of a failure condition the instrument cluster displays a text message of SERVICE PWR STEERING. In addition to responding to the Power Steering Malfunction message, the instrument cluster also displays the failure message to the operator if the instrument cluster does not receive the high speed CAN message for 1 second or more. This functionality guards against intermittent connection, network failures, or complete power steering control module/system failures. The instrument cluster turns the Power Steering Malfunction message on or off as directed by the power steering control module.

The power steering control module is on the high speed CAN. If 1 of the 2 bus wires becomes shorted to ground or voltage, communications on the CAN may not be possible. If there is an open in the network, communications may continue between some modules depending upon the location of the open circuit. Check the high speed CAN circuits 1908 (WH) and 1909 (BK), between the power steering control module C1463a and the DLC C251. Total resistance values must not be more than 5 ohms. If the resistance is more than 5 ohms, there is an open circuit in the high speed CAN, damage to the DLC C251, damage to the power steering control module C1463a, or a problem in the in-line connector. For removal and installation information, refer to POWER STEERING .