Hi, i have read some other posts and am still confused.

My mate changed the battery in my key fob without it being in the ignition for my x reg punto hgt and now my car is immobilised and i have the key code light showing.

I have looked in the manual and followed the instructions but i do not have the key code at all. I have two keys both are blue and both are remotes and they both do not now work.

I have read possible solutions to this problem being new ecu, reset ecu, but how do i get my key code and when i manage to emergency start it what do i do?

Some people have said they could not get anything out of fiat about this i just dont have a clue and wont be able to afford massive repairs if thats what it is.
I will really appreciate any help as i need my car. cheers.

Just renewing the battery shouldn't cause this sort of aggro. You mention needing a code to do an emergency start. I think Fiat don't supply the card with the code on it for UK customers (insurance companies requested that). Anyway, I think if you had that code and used the procedure, something would need to be reset.

Back to the new battery in the remote: These systems use a rolling code, i.e. each time it is used it creates a new code (stops people with scanners detcting your code). After fitting a new battery, the key probably needs re-synchronising to the car. I'm not familiar with the Fiat system but another car I had needed you to hold the button down on the remote for several seconds after fitting a battery (can't remember whether this was to be done in range or out of range of the car though). May be worth experimenting (or perhaps ignore me and wait for someone to post who can speak from experience!).

red

Thanks. I thought it would be a simple thing to but I literally drove to a shop, bought some batteries and when I got home changed it and went to go out again it would not start. the key code light is on. I haven't got a a clue.

Does the key lock/unlock the doors remotely as it's supposed to?

No it had stopped working for a few weeks so I assumed it was the battery and changed it and now it has immobilised my car and the remote does still not work

OK, basics first. Are you CERTAIN that the new battery is the correct one, and that it's correctly fitted? I know it sounds patronising but you need to eliminate the simple answers first.

yes it is exactly the same as the one I took out. A 2032 lithium battery. When i put it in and tried to start my car the key code light appeared and now it just turns over and wont start at all

Does sound rather like an immobiliser problem, poss ECU. Have you looked round the engine bay and checked all the wiring, I know that a loose earth around the immobiliser can cause the car not to start, though that shouldn't stop the doors from locking/unlocking.

Without having the car here to poke around there's not much more I can suggest. I'm sure one of the more knowledgable guys on here will be able to help you out!

Yeah I have had a poke around and all of the wiring is fine. I have never had a problem with it before and as soon as I change the battery I get the immobiliser light coming on.
I tried to do the emergency start but after reading on here I found that they didnt release the key code for U.K models. If I did get this code does anyone know what i would do after an emergency start?

I'm unsure of the remote key but is there any change the transponder chip has fell out?

Have you got a spare key?

Also the transponder is battery less so wont be affect by the fob.

The transponder chip is still in there it was loose I admit but my key has been rattling for ages and there has been no problems.

Yeah I tried my spare and it the key code lights still there. Nothing changes

The transponder pickup goes straight from the ring around the ignition to the internal fusebox, check the wiring.

Also the key information is stored in a eeprom chip in the internal fusebox and wont get erased etc.

Also the ring is just a coil of wire so you could test for resistance to make sure its ok.

okay yeah i will have a look.

Its just wierd that it happened straight after the battery was changed

I just read in the handbook that i should have changed the battery whilst the keys are in the ignition and turned to MAR. Is that what i have done wrong?

that wont affect the immo / transponder it will be to make sure the remote function works.

Although you could try doing it again, and see if at least the doors open with the remote, if so the transponder must be working.

I s the transponder normally connected to the chip because mine is not. It rattles around but it has been for ages with no problems key code wise