The type 2A SPS (Single Point Sensing) 2A airbag control unit by TRW fitted to the Discovery series II. It has a Single Point Sensor located inside the ECU itself and has capabilities for the addition of optional seat belt pretentioners and the passenger airbag. The ECU also stores the VIN number of the vehicle which can be changed and supplies lots of other settings and information too. Of course it also has a very extensive self diagnostic capability which utilises the fault code memory reading and clearing functions too.