Instrument panel

The sensor consists of a fine, flexible plastic plate that is adhesive on the side in contact with the seat padding and contains an electrical circuit that controls its operation. The plate covers the entire seat cushion area except the two sides. It fits between the padding and trim without altering the functional, aesthetic and ergonomic properties of the seat.

A passenger's presence on the seat is therefore detected even if the passenger sits incorrectly and regardless of whether the seat belt is worn or not.

The sensor is also designed to be compatible with a seat heater (available as an option). If a heater is present, the sensor is located underneath it.

The system is adjusted to detect a weight of at least 12 kg under all service conditions (from -35 to +70°C). For lower weights, the reponse depend on service conditions (temperature, shape and position of the weight, trim type, presence or absence of a heater.

The passenger presence sensor and its branch of wiring are monitored continually during car use. The diagnostic function checks for short-circuits or open circuits.

In the case of sensor malfunction, sensor readings are ignored and the system behaves in the same way as a conventional system, maintaining the passenger front and side bags active. The red failure warning light stays on.

Instrument panel

A. Air bag system failure warning light

ELECTRONIC CONTROL UNIT FOR AIR BAG SYSTEM AND PASSENGER PRESENCE SENSOR (PPD)

The air bag system fitted to the 1999 Fiat Bravo-Brava range comes with a new electronic control that differs from the previous system in the addition of a connection to the passenger presence sensor and the integration of control functions.