Satellite Acceleration Sensor

Vehicles equipped with side impact airbags use two impact or Satellite Acceleration Sensors (SAS). One is located on each respective side body B-pillar.

The satellite acceleration sensors are electronic accelerometers that sense the rate of vehicle deceleration and when combined with the Occupant Restraint Controller (ORC) accelerometer provides verification of the direction and severity of a side impact. Each sensor also contains an electronic communication chip that allows the unit to communicate the sensor status as well as sensor fault information to the microprocessor in the ORC.

The Satellite Acceleration Sensor (SAS) provides verification of the direction and severity of the side impact to the Occupant Restraint Controller (ORC). The ORC controls both the right and the left right side seat airbags. In the event of a side impact the ORC will send an electronic signal to deploy the appropriate seat airbag. The SAS periodically transmit the acceleration data to the ORC by modulation of the current on the power supply.

The accelerometer pulses are sent to a microprocessor, which contains a decision algorithm. When an impact is severe enough to require airbag protection, the ORC microprocessor sends a signal to deploy the side airbag that completes the electrical circuits to the right or left side airbag. The ORC is calibrated for the specific vehicle and reacts to the severity and direction of the impact.

The ORC microprocessor continuously monitors all of the passive restraint system electrical circuits to determine the system readiness. If the ORC detects a system fault, it sets a Diagnostic Trouble Code (DTC) and controls the airbag warning indicator operation accordingly. The side impact sensors receive battery current and ground through dedicated driver and passenger sensor signal and ground circuits from the ORC. If the sensor is dropped it must be replaced. Disconnect the battery or remove both airbag fuses before servicing impact sensors.