Occupant Weight Sensor (OWS) (USA/CDN Only)

Fig 1: Identifying Occupant Weight Sensor (OWS) (USA/CDN Only)

Courtesy of VOLVO CARS OF NORTH AMERICA.

The occupant weight sensor (OWS) consists of three interactive components:

• The pressure sensor, installed under the front passenger seat
• Belt force sensor, mounted in the seat frame on the outside of the front passenger seat
• Occupant weight sensor module, installed under the front passenger seat.

The pressure sensor and occupant weight sensor are linked via a hose. The pressure sensor registers the pressure to which the seat is exposed, for example when someone is sitting in the car. Information from the belt force sensor is also used to ensure the good performance of the system. The belt force sensor informs the occupant weight sensor module with what force the belt is tensioned. This is done because the pressure measured by the pressure sensor can be affected by the passenger fastening the seatbelt tightly. This means that the passenger exerts greater pressure on the seat than during normal seat belt use. The passenger is then interpreted as being heavier than he or she is. The occupant weight sensor module uses the information from both the pressure sensor and seatbelt force sensor to calculate the actual weight of the passenger. The occupant weight sensor (OWS) transmits continuous signals to the supplemental restraint system module (SRS) and occupant weight sensor (OWS) on the local CAN network. If the occupant weight sensor (OWS) does not function correctly the supplemental restraint system module (SRS) will:

• disable the front passenger airbag
• light the passenger airbag warning lamp (PAD) in the roof console
• light the SRS (supplemental restraint system) warning lamp and display the alert message in the driver information module (DIM).

If a fault occurs in any of the components the following should be noted:

• The pressure sensor and occupant weight sensor module must be replaced at the same time
• The seat belt force sensor is replaced separately.