Firebird V6-3.8L VIN K (1995)
Shift Interlock: Initial Inspection and Diagnostic Overview
Circuit Operation - Brake Transaxle Shift Interlock
The Brake Transmission Shift Interlock (BTSI) is designed to interrupt shifting when energized. The BTSI is energized whenever the Ignition Switch is
in "RUN", "BULB TEST" or "START" and is disabled when the brake pedal is depressed. The Brake Switch Assembly receives Ignition voltage from
Gages Fuse #9 in "RUN," "BULB TEST" and "START." The TCC/Shift Interrupt Switch is part of the Brake Switch Assembly and is normally closed,
providing voltage to the Brake Transmission Shift Interlock Solenoid. The BTSI Solenoid gets its ground path through CKT 434 then through the
Transmission Range Switch only when the Transmission Range Switch is in the "PARK" or "NEUTRAL" position and then to ground through CKT 451.
When the BTSI Solenoid receives voltage and the Transmission Range Switch is in the "PARK" or "NEUTRAL" position, the BTSI Solenoid is
energized and prevents the Transmission Shift Lever from being moved out of "PARK" or "NEUTRAL." When the brake pedal is depressed, the Brake
Switch opens, removing voltage from the BTSI Solenoid. This de-energizes the BTSI Solenoid, allowing operation of the Shift Lever.
Troubleshooting Hints - Brake Transaxle Shift Interlock
Perform before beginning System Diagnosis.
1. If Gages Fuse #9 is open, refer to Chart #3. See: Symptom Related Diagnostic Procedures/Symptom Diagnostic Charts - Brake Transaxle Shift
Interlock/Chart #3 Gages Fuse #9 Repeatedly Blows When Ignition Is on
2. Check Brake Switch Assembly for proper adjustment.
3. If Transmission Shifter does not shift out of "PARK," check linkage and cable for binding.
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Check for a broken (or partially broken) wire inside of the insulation which could cause system malfunction but prove "GOOD" in a
continuity/voltage check with a system disconnected. These circuits may be intermittent or resistive when loaded, and if possible, should be
checked by monitoring for a voltage drop with the system operational (under load).
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Check for proper installation of aftermarket electronic equipment which may affect the integrity of other systems (Refer to "Diagnostic
Aids/General Troubleshooting Procedures,"). See: Diagrams/Diagnostic Aids
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Refer to System Diagnosis. See: Component Tests and General Diagnostics
