GM currently uses four different Passenger Sensing System technologies developed by four different suppliers. All of these technologies are designed to meet the federal requirements. The four passenger sensing technologies that are currently in GM vehicles are Delphi's PODS-B, Elesys, IEE and Aisin.
Delphi PODS-B
The Delphi PODS-B system uses a silicone filled bladder. The occupant's weight generates a pressure input onto the bladder through the seat cushion. The system doesn't measure all of the occupant's weight because some of the weight is distributed through the occupant's legs and not onto the system's bladder. Tension in the safety belt generates an additional input to the system. The PODS-B control module compares the adjusted weight estimate to a threshold and communicates an air bag ON or OFF decision to the air bag control module. All of GM's 2003 and 2004 model year vehicles that are equipped with a Passenger Sensing System use the PODS-B system with additional implementations of this technology in some 2005 and later models.
Elesys
The Elesys system is a capacitive system which uses flexible sensors to determine the occupant's presence, relative amount of mass and relative position on the seat. The sensors' input is used to help discriminate between a child in a child restraint, a child sitting directly on the seat and an adult-sized occupant sitting directly on the seat. GM first implemented the Elesys system in the 2005 model year on the Buick Lacrosse, with additional implementations beginning in the 2006 model year.
IEE
The IEE system uses an array of Force Sensing Resistor cells located between the seat trim and the top surface of the seat cushion foam. It uses pattern recognition as well as area and load on the seat to communicate the air bag ON or OFF decision to the air bag control module. GM first implemented the IEE system in the 2005 model year on the Cadillac CTS, with additional implementations beginning in the 2006 model year.
Aisin
The Aisin system uses four seat rail mounted sensors that measure the weight of the occupant in the seat. That information is relayed to the air bag control module and used to determine the air bags on/off decision. The Pontiac Vibe began using this system in the 2005 model year. All of these technologies comply with Federal Motor Vehicle Safety Standard 208's requirements. In addition, General Motors and its Passenger Sensing System suppliers have developed a variety of internal considerations that are used to help evaluate system performance.