Shaft Lock Module
Description
A shaft lock module (1) is part of the premium version of the Vehicle Theft Security System (VTSS). The premium version of the VTSS is only available in vehicles built for certain markets, where the additional features offered by this system are required. The shaft lock module is located in a die cast metal bracket on the lower end of the steering column housing below the instrument panel in the passenger compartment. This unit is designed to work in conjunction with the Wireless Ignition Node (WIN) to control a locking bolt (2) that engages a machined slot in the steering shaft to prevent shaft rotation whenever there is not a valid FOB with Integrated Key (FOBIK) present in the ignition switch on the instrument panel.
The die cast aluminum shaft lock module housing has a series of integral engagement tabs and slide tabs that engage matching slots and channels integral to the mounting bracket on the steering column. When the module is fully engaged in the mounting bracket, two spring clips (3) on the module engage the bracket, locking the module securely into place. Concealed within the module is the electronic circuitry of the module, and a bi-directional electric motor that actuates the locking bolt. The module is connected through an integral connector receptacle (4) to the vehicle electrical system through a take out and connector of the instrument panel wire harness.
The mounting provisions for the shaft lock module are designed to resist unauthorized tampering. The module cannot be removed from the steering column while the locking bolt is in the locked position, or while the steering column is installed in the vehicle.
The shaft lock module unit cannot be adjusted or repaired and, if ineffective or damaged, it must be replaced.
Operation
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 serial data bus for bi-directional communication with the Wireless Ignition Node (WIN). The WIN then stores a Diagnostic Trouble Code (DTC) and sends an electronic error message to the Cab Compartment Node (CCN), over the Controller Area Network (CAN) data bus, and a >>SERVICE COLUMN LOCK<< message will appear in the instrument cluster display.
The shaft lock module continuously monitors inputs from the WIN and energizes the electric motor to move the locking bolt to the locked or unlocked position based upon that input. If the WIN indicates that the FOBIK present in the vehicle or the ignition switch is invalid, the locking bolt remains in the locked position. When the WIN indicates that a valid FOBIK is present in the vehicle or the ignition switch, 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 a key remains in the ignition switch.
The shaft lock module receives ground at all times through a hard wired 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 key is removed from the ignition switch. These connections allow the module to remain operational, regardless of the ignition switch position.
For added system security, the shaft lock module learns a unique Secret Key code from the WIN over the serial data bus upon initialization. This code is stored in the memory of the module and cannot be changed. Therefore, if the WIN requires service replacement, a new shaft lock module will also be required. Another security code, called a PIN, is used to gain access to the WIN Secured Access Mode. The Secured Access Mode is required during service to initialize a new shaft lock module. The shaft lock module cannot be adjusted or repaired and, if ineffective or damaged the shaft lock module must be replaced. Whenever a shaft lock module is replaced the WIN must also be replaced. To remove a locked shaft lock module from a removed steering column.