Module, Shaft Lock: Operation

WARNING: This page is about a different car, the 2020 Chrysler 300 and 2019 Chrysler 300. However, it is still accessible from the selected car via links, so may be relevant.

The shaft lock module is designed to work in conjunction with the Radio Frequency Hub (RF-Hub) to control a locking bolt that engages a machined slot in the steering shaft to prevent shaft rotation whenever the status of the ignition is in Lock. The shaft lock module can only be unlocked when the presence of a valid FOB with Integrated Key (FOBIK) unit is detected in the front seat area of the vehicle and the status of the ignition is RUN/START.

The electronic circuitry within the shaft lock module contains all of the logic circuits and components to monitor and control the operation of the shaft locking bolt. The module uses a dedicated Local Interface Network (LIN) serial data bus for bi-directional communication with the RF-Hub. If the module detects a problem with the positioning or operation of the locking bolt, it sends an error message to the RF-Hub. The RF-Hub then sets and stores a Diagnostic Trouble Code (DTC) and sends an electronic error message over the Controller Area Network (CAN) data bus to other Electronic Control Units (ECUs) in the vehicle.

The shaft lock module continuously monitors inputs from the RF-Hub and energizes the electric motor to move the locking bolt to the locked or unlocked position based upon that input. If the RF-Hub indicates that the FOBIK present in the vehicle is invalid, the locking bolt remains in the locked position. When the RF-Hub indicates that a valid FOBIK is present in the vehicle and the status of the ignition is RUN or START, the shaft lock module operates a motor to move the locking bolt to the unlocked position. However, to prevent inadvertent column locking due to a failure while the vehicle is being operated, the module cannot move the locking bolt from the unlocked position to the locked position as long as the status of the ignition remains RUN or START.

The shaft lock module receives a path to ground at all times through a hardwired remote ground point. The module receives battery voltage to operate and to move the locking bolt in the unlocked direction on a B(+) circuit, and receives battery voltage to operate the locking bolt in the locked direction only when the status of the ignition is OFF and other data from the RF-Hub allows it.

For added system security, the shaft lock module learns a unique Secret Key code from the RF-Hub over the LIN data bus upon initialization. This code is stored in the memory of the module and cannot be changed. Therefore, if the RF-Hub requires service replacement, a new shaft lock module will also be required. Another security code, called a Personal Identification Number (PIN), is used to gain access to the RF-Hub Secured Access Mode. The Secured Access Mode is required during service to initialize a new shaft lock module. Before replacing the shaft lock module or the RF-Hub see the Module Replacement and Programming Order Guide for the proper sequence. Refer to IMMOBILIZER COMPONENTS AND REPLACEMENT GUIDE .