Seat Belt Tension Sensor - BTS

The Belt Tension Sensor (BTS) is designed to measure belt tension as an input to a passenger Occupant Classification System (OCS). It is used to detect high cinch loads associated with child seats and compensate for the seat cushion load to correctly classify occupant size. When a load is applied to the seat belt, the belt tension sensor measures the load. As the load changes, the circuitry of the belt tension sensor changes the output voltage of the sensor. The belt tension sensor receives a nominal five volts and a ground through dedicated hardwired circuits from the OCM. The OCM then monitors the belt tension sensor output voltage on a dedicated hardwired data communication circuit. If the vehicle has experienced any impact(s) resulting in deployment of a pyrotechnic device of any kind (airbag, seatbelt tensioner, side curtain, etc.) within the vehicle, the entire passenger seat belt retractor assembly, including the BTS, shall be replaced. Additionally, if the seat belt webbing has become cut, frayed, or worn; or if the stitching has become damaged in any way, the entire passenger seat belt retractor assembly, including the BTS, shall be replaced. The belt tension sensor cannot be repaired and, if faulty or damaged, the entire passenger side front seat belt and retractor unit must be replaced. The OCM Verification Test will also provide a BTS Verification procedure to verify the BTS function. This verification procedure requires the Miller Special Tool #8828.