Shift Interlock: Description and Operation
MECHANISM-BRAKE TRANSMISSION SHIFT INTERLOCKDESCRIPTION
The Brake Transmission Shifter/Ignition Interlock (BTSI) is a cable operated system that prevents the transmission gear shifter from being moved out of PARK without the proper driver inputs. The system also contains a solenoid that is integral to the shifter assembly. The solenoid works in conjunction with the park lock cable to permit shifter movement out of PARK when the brake is depressed and prevents shifter movement into REVERSE unless a shift into REVERSE is permitted.
A BTSI override (2) is provided on the side of the shifter mechanism (1) to allow the vehicle to be shifted out of PARK in the event of an electrical failure.
OPERATION
The Brake Transmission Shifter/Ignition Interlock (BTSI) is engaged whenever the ignition switch is in the LOCK (1) position. 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 solenoid in the shifter assembly is energized when the ignition is in the ON position and the brake pedal is depressed. When the key is in the ON 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 position, unless the shifter is in the gated PARK position.
The above 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.
BTSI Override
In the event of an electrical failure, the vehicle can be shifted out of PARK by using the following procedure.
1. Turn the key to the ACC or ON position.
2. Remove the liner to the cubby bin to the right side of the shifter.
3. Depress the BTSI override (2) on the side of the shifter assembly (1).
4. While the override is depressed, move the shifter out of the PARK position.
5. Return the cubby bin liner to its original location.