Impact Sensor: Description and Operation

The front air bag sensor unit is a mechanical G sensor that cannot be disassembled. The G sensor is an eccentric mass rotating on a fixed axis and held in place by a spring. If deceleration exceeds a predetermine value, the rotor moves and at a certain point turns a switch On. If the safety switch is also On, the air bag inflator is ignited, Fig. 1.






Front sensors are placed in a case filled with potting material to protect them from the elements and ensure reliability. The switch is gold-plated for reliability.
The front sensor is equipped with an electrical connection check mechanism.
Ensure this mechanism is securely locked when connecting connector. If connector is not locked, SRS malfunction or diagnostic trouble codes (DTCs) will generated.
Front air bag sensors are located on inside of each front fender on ES300,
GS300, 1994 LS400, 1994-95 SC300 and SC400 models.