Shift Interlock: Description and Operation

The Park Relay is supplied battery voltage by the PCK/REV fuse through CKT 1940 (ORN) to terminal "A1" and ignition voltage by the CRUISE fuse through CKT 339 (PNK) to terminal "A3." The Body Control Module (PZM) receives Park/Neutral Position (PNP) Switch status from the Powertrain Control Module (PCM) by Class 2 serial data communications. When the PZM sees that the vehicle is in "PARK" it energizes the Park Relay by grounding CKT 434 (ORN/BLK). When the Park Relay has been energizes by the PZM voltage is supplied from terminal "B3" of the Park Relay to terminal "A" of the Stop/BTSI/Cruise Brake Switch through CKT 275 (LT GRN). When the brake pedal is in the rest position (not pressed), battery voltage is supplied from terminal "B" of the Stop/BTSI/Cruise Brake Switch through CKT 1135 (DK GRN/WHT) to terminal "A" of the Shift Interlock Solenoid. The solenoid, grounded by CKT 850/50 (BLK), energizes locking the shifter in park. when the brake pedal is in the applied position (pressed), the Stop/BTSI/Cruise Brake Switch opens removing the voltage from the Shift Interlock Solenoid. The solenoid de-energizes, unlocking the shifter. When the PZM sees that the vehicle is no longer in "PARK" it de-energizes the Park Relay, unlocking the shifter.