What’s In A Seat: Occupant Classification System (OCS)

As vehicles are becoming more advanced, we are finding technology where it never was before. Sometimes it is in plain sight, such as infotainment systems, GPS, and head-up display. However, sometimes it is concealed in places one may not expect.

Let’s take a look at automotive seats, they do far more now than just provide a comfortable place to sit. Seats now may have an occupant classification system (OCS), airbags, haptic feedback (vibrating seats), or heated and cooled seats. These systems typically go beyond simple switches and relays and rely on control modules and computers to make them function.

OCS have been an integral part of supplemental restraints systems (SRS) since the early 2000’s. They are an important part of making sure the air bag properly protects the passenger. Designed for detecting passenger presence and weight, they may also be able to detect if a child or small adult is in the seat. This is vital to making sure the passenger air bag deploys only under the correct circumstances.

The system typically consists of a weight sensor, seat position sensor, and a control module. The weight sensor may be a bladder-style sensor, strain gauges, or a pressure-sensitive mat. Often, there is a switch for disabling the passenger air bag.

Vehicles may require replacement of the weight sensor or control module after a collision, while other may only require a calibration. In addition, a calibration may be required after the seat is removed or replaced. Always refer to the vehicle-specific service manual for the proper requirements and procedures.

It is important to know if a vehicle is equipped with these features, what parts are used in the system, and where they are located. This will enable you to check for proper operation to ensure a complete, safe, and quality repair.

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