Shaft Lock Module - Operation

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 Electronic Ignition Switch (EIS) (also known as the Electronic Ignition Switch/Central GateWay/EIS/CGW or EZS). If the module detects a problem with the positioning or operation of the locking bolt, it sends an error message to the EIS, which then stores a Diagnostic Trouble Code (DTC).

The shaft lock module continuously monitors inputs from the EIS and energizes the electric motor to move the locking bolt to the locked or unlocked position based upon that input. If the EIS indicates that the key present in the ignition lock cylinder is invalid, the locking bolt remains in the locked position. When the EIS indicates that a valid key is present in the ignition lock cylinder, 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 ignition is not turned to the 0 (OFF) position.

The shaft lock module receives ground at all times through a hard wired remote ground point. The module receives battery voltage to move the locking bolt only when the ignition switch is in the 0 (OFF) position.

The hard wired inputs to the shaft lock module may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. However, conventional diagnostic methods will not prove conclusive in the diagnosis of the shaft lock module or the electronic controls or communication between other modules and devices that provide some features of the steering shaft lock control. The most reliable, efficient, and accurate means to diagnose the shaft lock module or the electronic controls and communication related to shaft lock module operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.