Hi, I own Brava 1996 model and had similar problem. Fiat Key Code orange light often used to pop up. I gave it to a mechanic shop that do ELECTRICAL work. They sorted the issue and my car now works fine.
If ELECTRICAL interference is NOT the issue, other reasons could be :
1. The FIAT Code is disabled/or not being recognised, In this case, you would need the MASTER key (red) to re-configure the ECU/Immobilizer.
2. Sometimes the Fiat Key (transponder) itself may be malfunctioning so you need to get a spare Key.
3. You battery connectors may have oxidation. Cleanup the connectors.
4. The fiat key ( it has got a transponder), key code sensor, Key Code Box, Immobilizer and ECU - all have to work in sync. If there is malfunction in anyone you will have the problem.
5. There is something called as IMMOKILLER ( a software), you may google to find more about it. Do not know if this works.
If nothing works, try to get a VIRGIN ECU ( uncoded ECU). This will however make the car susceptible to car thefts.
As the last resort you have the FIAT Authorized Service Centers. But the charges are huge.
However, first check the electrical. If there is electrical interference, the mechanic will have it sorted. If not try other possibilities.
I know it's really a headache. Wishing you all the best, friend !
If ELECTRICAL interference is NOT the issue, other reasons could be :
1. The FIAT Code is disabled/or not being recognised, In this case, you would need the MASTER key (red) to re-configure the ECU/Immobilizer.
2. Sometimes the Fiat Key (transponder) itself may be malfunctioning so you need to get a spare Key.
3. You battery connectors may have oxidation. Cleanup the connectors.
4. The fiat key ( it has got a transponder), key code sensor, Key Code Box, Immobilizer and ECU - all have to work in sync. If there is malfunction in anyone you will have the problem.
5. There is something called as IMMOKILLER ( a software), you may google to find more about it. Do not know if this works.
If nothing works, try to get a VIRGIN ECU ( uncoded ECU). This will however make the car susceptible to car thefts.
As the last resort you have the FIAT Authorized Service Centers. But the charges are huge.
However, first check the electrical. If there is electrical interference, the mechanic will have it sorted. If not try other possibilities.
I know it's really a headache. Wishing you all the best, friend !