Brake Transmission Shift Interlock (BTSI)

The brake transmission shift interlock (BTSI) system prevents the automatic transmission from being shifted out of PARK unless the brake pedal is depressed.

When the brake pedal is depressed, the BTSI solenoid releases a lock paw, enabling the shift linkage to move and the shift lever to operate.

When service operations are required, the BTSI system can be overridden. This is done by turning the ignition switch to OFF (not locked) and removing battery voltage from the solenoid.