Hi gent`s , got a little time during the xmas holiday. Asked some of my electronics friends. They have experience with troubleshooting aircraft fire bottle squibs....ie......just like the air bag.....they get a signal and blow the explosive charge which in this case, empties the fire bottle into the engine or freight hold in the event of a fire. They advised to use a recommended moving coil type meter but should be o.k. , but not recommended , ( at your own risk ) with a digital multimeter. Borrowed a meter and went about it .
Took the precautions, Battery disconnected for 30 min at least, Initially got confused by the side airbag sensor which is mounted on the "b" post beside the pretensioner and has the same yellow connector blocks. The wiring diagram in e-learn is good on this ...the lead in is ....airbag- description, Airbag- wiring diagram, Airbag-location of components, airbag-functional description .
The moving coil meter packed up.....giving unreliable readings so I took a chance using my digital multimeter. Disconnected the connectors to the pretensioner and measured the resistance. With the ohmmeter set to 200 on the scale the readings were 00.7 on each pretensioner ( the good and the bad ) moving further up the scale really only gave me zeros. ......which now leads me to believe the problem lies with the airbag ECU or its connections. The drivers pretensioner showing the fault would not reset (as before ) using Fiatecuscan, after remaking all these connections at the pretensioners...........next step ECU .................rgds...........Dannyboy.