Hi, does anyone know why there are some many alleged different types of sensors used for the same purpose of high temperature exhaust gas, and why is there such a variation in cost. does any know where I can purchase exhaust sensors for my 2006 with PDF multipla at a sensible price? why can't I pay £6 for a thermocouple to measure 200-1200 C as opposed to £128 from Italy? If any one help?:

I could be wrong but I don't believe they are temperature sensors, certainly not if you have a diesel. My understanding is that they are pressure sensors that sense the differential of pressure between the front (inlet) of the DPF and the Exhaust (rear) of the DPF. When the differential varies over a certain degree it is recognised as the DPF blocking and the ECU is invoked to initiate a regen.

many thanks for your reply. there is a separate tube from the particle filter up to a pressure sensor on the bulkhead so i would have thought that measured the pressure although not differential. If the filter was getting blocked there would also be a change in temperature due to the restricted flow, If anyone can confirm pressure or temperature sensors ESBNTS200/054946280034/FGP55199053 and ESBNTS200/0603184707/63/FGP5519700, Many thanks for any more help greatfully received.