Occupant Monitoring

There are 2 types of occupant monitoring:

On all markets except North American Specification (NAS) market, vehicles have an occupant detection sensor.
On NAS market, vehicles have an occupant classification sensing.

Occupant Detection Sensor

Courtesy of JAGUAR LAND ROVER NORTH AMERICA, LLC

ITEM	DESCRIPTION
1	Occupant detection sensor

The occupant detection sensor is installed in the cushion of the front passenger seat, between the foam padding and the cover. The sensor consists of a foil contact circuit, embedded in a plastic sheet. Weight on the sensor reduces the resistance of the circuit, which is detected by the Body Control Module/Gateway Module (BCM/GWM).

The occupant detection sensor has no interface with the Supplementary Restraint System (SRS). It only provides an input to the BCM/GWM for the seatbelt reminder function.

For additional information, Refer to: SEATBELT SYSTEM .

Occupant Classification Sensor System

Courtesy of JAGUAR LAND ROVER NORTH AMERICA, LLC

ITEM	DESCRIPTION
1	Seatbelt pretensioner
2	Seatbelt buckle
3	Seatbelt tension sensor
4	Anchor bolt
5	Pressure pad
6	Occupant Classification Sensor Control Module (OCSCM)

In North American Specification (NAS) markets where seatbelt usage is infrequent, additional technology is used to classify the occupant of the front passenger seat. The occupant classification sensor system provides seat load data to the Restraints Control Module (RCM).

The occupant classification sensor system consists of:

The Occupant Classification Sensor Control Module (OCSCM), installed under the front passenger seat.
A pressure pad, installed under the cushion of the front passenger seat, which is connected to the OCSCM.
A seatbelt tension sensor, integrated into the anchor point of the front passenger seatbelt.

The pressure pad is a silicone fluid filled bladder. Any load on the pressure pad is detected by the OCSCM. The seatbelt tension sensor is a strain gauge which measures the load applied by the seatbelt anchor to the anchor bolt. The sensor is located in the lower seatbelt anchor point.

CAUTION: The Occupant Classification Sensor Control Module (OCSCM), hose and pressure pad form a sealed assembly and must not be disassembled. The assembly can only be replaced as part of the occupant classification system service kit. The service kit includes the seat cushion as during the assembly the OCSCM is specifically calibrated to the cushion where each cushion has a unique calibration.

The OCSCM supplies a reference voltage to the seatbelt tension sensor and, from the return signal, measures the load acting on the seatbelt anchor. The measurement is used to produce a correction factor for the load acting on the pressure pad. The tightness of the seatbelt affects the load acting on the pressure pad, so without the correction factor the OCSCM cannot derive an accurate occupancy status.

The OCSCM translates the load readings into a seat occupancy status and transmits the result to the RCM. The OCSCM transmits the signal on the High Speed (HS) Controller Area Network (CAN) powertrain systems bus.

The RCM monitors and processes the data from the OCSCM before making an airbag deployment decision. The system is designed to take account of several variables in addition to weight. Including the inclination of the vehicle and exact position and structure of the weight on the seat.

This protects against inadvertent airbag deployment. For example, if the seat were occupied by an infant in a booster seat, or an unrestrained but very lightweight adult. In both these cases the airbag would be disabled. The occupant classification sensor system forms part of a strategy to control passenger airbag deployment depending on the occupancy scenario.