Shift Interlock: Description and Operation

DESCRIPTION








The Brake/Transmission Shift Interlock (BTSI) system consists of a cable that connects the ignition cylinder to the transmission gear shifter and prevents the transmission gear shifter from being moved out of park when the ignition key is in the LOCK or ACC positions (Fig. 283). The cable also features an electro-magnetic solenoid (Fig. 284) which prevents shifter movement when the ignition key is in the ON/RUN position unless the brake pedal is depressed.

OPERATION





The Brake Transmission Shifter/Ignition Interlock System (BTSI) is engaged, preventing the transmission gear shifter from being shifted out of Park whenever the ignition key/switch is in the LOCK or ACCESSORY position (Fig. 283). An additional electrically activated feature will prevent shifting out of the PARK position unless the brake pedal is depressed at least one-half inch. A magnetic holding device integral to the interlock cable is energized when the ignition is in the ON/RUN position. When the key is in the ON/RUN position and the brake pedal is depressed, the shifter is unlocked and will move into any position. The interlock system also prevents the ignition switch from being turned to the LOCK or ACCESSORY position, unless the shifter is in the gated PARK position.
The following chart describes the normal operation of the Brake Transmission Shift Interlock (BTSI) system. If the "expected response" differs from the vehicle's response, then system repair and/or adjustment is necessary.





INTERLOCK OPERATION WITH STSI