Shift Interlock: Description and Operation
CIRCUIT OPERATIONShift Lock Solenoid Operation
The purpose of the Shift Lock Solenoid is to prevent the driver from shifting out of "P" into another gear without first depressing the brake pedal. This is accomplished via the Shift Lock Control Module. Battery voltage is applied to the Shift Lock Control Module through the ECU/IG Fuse and Junction Block 3 when the ignition switch is in the "ON" and "START" positions. The Shift Lock Control Module is permanently grounded at G200 through Junction Block 3 and Junction Connectors 1 and 3. With both power and ground provided, the Shift Lock Control Module will apply voltage and energize the Shift Lock Solenoid, thus unlocking the manual selector lever if the following signals are present simultaneously: a Brake Signal (indicating that the brake pedal is depressed) and a P Signal (indicating that the manual selector lever is in the "P" position with the button on the manual selector lever released).
The Shift Lock Control Module receives the Brake Signal through the Stoplamp Switch, Junction Block 1 and Junction Block 3 whenever the brake pedal is depressed. The P Signal is received through the Shift Lock Control Switch when the manual selector lever is in the "P" position with the button released. The Shift Lock Solenoid is grounded through the Shift Lock Control Module and energizes as soon as voltage is applied. The Shift Lock Solenoid energizes to unlock the button on the manual selector lever. The button on the manual selector lever acts as a mechanical switch, and when depressed, de-energizes the solenoid. The solenoid, however, does not return to the de-energized position, but is held in place mechanically. It is by this that the manual selector lever can be moved from the "P" position.
Ignition Keylock Solenoid Operation
Battery voltage is applied to the Shift Lock Control Module through the CIG-RADIO Fuse, the Audio Alarm Module and Junction Block 3 when the ignition switch is in the "ACC" and "ON" positions. The Shift Lock Control Module is permanently grounded at G200 through Junction Block 3 and Junction Connectors 1 and 3. With power, ground and an R,N,D,2,L Signal from the Shift Lock Control Switch, the Shift Lock Control Module will apply voltage and energize the Ignition Keylock Solenoid, thus locking the ignition key into the lock cylinder and preventing the ignition switch from being turned to the "LOCK" position.
This prevents the ignition key from being removed from the lock cylinder until the manual selector lever is in "P." The R,N,D,2,L Signal is received whenever the manual selector lever button is depressed or when the lever is in a position other than "P." The Ignition Keylock Solenoid, which is grounded at G204 through Junction Block 2, remains energized until the manual selector lever is returned to "P" with the manual selector button released. When the lever is returned to the "P" position with the button released, the solenoid de-energizes, thus allowing for the ignition key to be turned to "LOCK" and for its removal from the ignition lock cylinder.