Hi, recently my keys were stolen and after being quoted an extortionate fee from Fiat to replace them, I bought an ignition barrel, key and ECU second hand. After fitting them and putting the barrel back together the engine started at the first attempt but tried to start it again and it failed. The ignition can be switched on but the engine won't even turn over. Does anybody have any ideas about what could be wrong?

It is a mk2, 1.2 active sport.

Thanks.

do you have any diagnostic equipment? must be something simple tho.

thinking about it tho and dont quote me on this but it could be that the doner ecu you have is or was mapped to the vehicle you took it from also is it exactly the right ecu?
make,model ect ect.. if it was me i would double check the make of the ecu compared to your old one. if all checks out then diagnostic would be my next approach. also double check all the wiring disconnect the ecu plugs and inspect before hooking up a diagnostic reader to it.

a must when swapping out the ecu is the same version make model year and so on unless you get hold of a virgin ecu in which case your car's sensors will feed the a virgin ecu all the info it needs. a little dicky bird is telling me its something to do with the key code embedded into the ecu if im honest. as its behaving like your trying to start the car with the right key however something isnt right with reading the key code to allow it to start.

Do you have a key code light on? Or does it just keep attempting to start? What happens when you put a bit of gas on when starting up?

Ben

another thing you can try is inside your ecu is a eeprom chip which stores most if not all the mapping data including the key code too. on some fiat ecu's they are removeable and you may as a suggestion try the eeprom chip from your old ecu and insert it into the doner and may solve it worth a look tho. you will need to search on how to take a marelli type ecu apart and eeprom removal.

Also check the earth strap on the throttle body, I had similar problem to you it started up or just about to and then failed, whipped airfilter off to find the earth strap had wiggled itself loose, this strap is a git for doing this and its common if this is either dirty or loose it will cause a non start and the immobilizer to stay on constantly, so it's worth checking this.

Ben

scdaniel2012 said:

Hi, recently my keys were stolen and after being quoted an extortionate fee from Fiat to replace them, I bought an ignition barrel, key and ECU second hand. After fitting them and putting the barrel back together the engine started at the first attempt but tried to start it again and it failed. The ignition can be switched on but the engine won't even turn over. Does anybody have any ideas about what could be wrong?

It is a mk2, 1.2 active sport.

Thanks.

Click to expand...

Hi mate,

If the car isnt even turning over, then I would suspect the ignition switch that you have just fitted or the connections to it. Especially as it started the first time. Take it apart again and check everything is secure and as it should be. Check fuse F3 in the engine bay fuse box.

If it were an ECU issue it should still turn over, if it were a CODE issue it should also still turn over, so they shouldn't be your issue.

Alan