I have a fault with my 2008 Fiat Bravo. I am no expert but from trial and error and a bit of google I think I have narrowed it down to a fault with the immobiliser. However I could be completely wrong.

The engine management light and the code error light (car with lock on it) stay lit.

The car won't turn over, it just makes a weird quick clicking sound and the speedo needle vibrates. The radio, lights work etc. I jumped started the car, and surprisingly it started straight away. So i assumed a battery issue, yet as soon as I turned off the key after letting it run for 30 minutes the exact same thing happened.

I find it strange that I cant start it with the key by itself, yet it jumps straight away no problem? Could it be that I just need a new battery? When I am driving the code error light stays on however.

I have replaced the key battery and got the same result, along with disconnecting the negative battery terminal. I sat it overnight for about 15 hours and reconnected to the exact same problem.

I have heard that it could be that the key is no longer being recognised by the immobiliser and to get this fixed by Fiat is around 250 pound. They have also quoted 102 pound per hour to diagnose the problem themselves. I am hoping that there is a cheaper solution than that?

All thoughts and possible solutions will be greatly appreciated!

You have a ground problem.
Use a multimeter to check the voltage between the gearbox and the negative battery terminal.
Get jumper cables put one end on the gearbox and the other on the negative battery terminal. it should start.

When you have another car jump start it the voltage from the 2 batteries can jump the gap or corrosion..allowing the car to start.

Reprogramming the key is a 10 minute job so it wont be £250. A new key could cost this but its unlikely you need one as the car starts. Try another car battery first. Gendan software might help. Contact them they are very helpful.