The warning light for the airbag on my Fiat Marea started lighting up, indicating a problem with the airbag. I read up on the issue, and found that it can be a problem with the wiring, and that once triggered the light would continue to illuminate until the fault was cleared in the onboard computer.
The first time I fixed this, I enlisted the help of a friend who borrowed an expensive diagnostic tool from his work. However, when it happened a second time I resolved to fix it myself.
I purchased an OBDII to USB tool, and found some free software that could talk to Fiat computers.
Unfortunately the connector on the car was made before OBDII connectors were standardised, and I didn't have an adapter. Not letting that stop me, a couple of paper clips, some (green) blu tak and a couple of crocodile clips solved the problem.
Once my laptop was wired to the connector, clearing the fault code was pretty simple.