I've got a problem with the airbag warning light on my 2002 punto. The fault light has come on. Does anyone have a wiring diagram so that I can check the connections.

The warning light won't go off until you clear the fault electronically and doing so tells you where the fault is, there is absolutely no point in playing around with the wiring because even if you do find and fix a fault the light will not go out.

Watch my video for how to clear airbag warning lights

Light is on again, I reckon the ecu is maybe dodgy. I cannot see the ecu with multiecuscan using red adapter I’ve looked at replacements and note that they have different colour rd labels and different numbers
Mine is blue label reference 51719092 & 331374. Does the replacement need to match exactly or does the label colour denote the model of ecu
Thanks

There is a known problem with Punto passenger airbag light coming on & staying on. Its an earth fault as it shares a common earth. Fiat's solution is to give the air bag its own earth. Fiat produced a replacement wiring harness that replace the wires from the ecu to the airbag on/off switch on the end of the dash panel. It was about £8 but now its closer to £55. It replaces the pink wire from the ecu to the on/off switch & has a single black wire that is secured onto one of the ecu mounting bolts/nuts. You could make your own but once replaced you'll need to clear any errors in the ecu. I was lucky because its a known problem I managed to find a car in a breakers yard which had the extra wiring harness as I wasn't goin to pay £55 for 2x bits of wire with connector & a nut & washer.

Thanks for advice, I’ve found a replacement ecu if the light stays on I’ll have a look at the wiring for the isolation switch. Does the switch earth the return to the ecu when the switch is in the isolate position. Do you know if the ecu numbers need to match on the replacement?