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Technical New Croma 2005 Multijet owner looking for some advice

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Technical New Croma 2005 Multijet owner looking for some advice

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Magnumwhite1

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Oct 26, 2018
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Hi, I recently purchased a Croma and have joined here to read about peoples experiences with them and to get some advice on issues ive had with the key fob. The fob would stop working after the car had been idle for 10 hours or more and only start working again one ide used the key in the door.

I changed the battery in the fob but this didnt make any difference. However around a month later the fob now only works for around 5 minutes after the car has been idle. Its as if the fob or receiver fall asleep after a certain time and only wake up again once the key has been used, the other thing to note aswell is that when the fob etc is "awake" and working the fob will actually work from distance.

Ive been searching the internet for people with the same issue but yet to find someone with the same symptoms.

Also the alarm goes off when I use the key and I have to turn it off with the fob and am concerned if the fob stops working altogether then I wont know how to turn the alarm off?

Any help on this would be massively appreciated.

Kind regards

Lee
 
Hi Lee. And welcome to FF.

The Croma wasnt a great seller in the UK.. so many mechanicals are sourced via GM related cars.

That might be a course to pursue..

Of course getting the body computer interrogated..then reset.. could well help also.

Charlie
 
I've never experienced or heard of this on any Croma.

However I had an issue with my 500X similar to yours where one key failed to work and when I tried the other that did as well. Somehow eventually (can't recall the details, but I did use the manual key) I got both keys to work.

My theory/explanation is as follows.

The key/fob/security system uses rolling codes. So on press 1, code X1 is sent. On Press 2 code X2 is sent, and so on. Now clearly key fob keys will get pressed accidentally or when out of range. This means the vehicles security system / key code system has to be able to cater with this and thus will have "look ahead" code sequences that are valid. However this list can not be unlimited so if a key fob key is permanently pressed when out of range of the vehicles key code unit/body computer then the "look ahead" list is exhausted and the transmitted code is deemed invalid.

Now this would be a permanent/hard problem unless there is some form of reset built in or the many hundreds / thousands of codes return back to the seed value (i.e. loop round again).

So my possible explanation / theory is that your key fob is button stuck and continually transmitting codes (or something is) and when you use a physical key to unlock the car the system accepts and resets.

In my case I've had plenty of occurrences where key fobs, my phone in tight trouser pockets has caused unwanted activation.

Can't be sure but worth following up at your end.
 
Last edited:
Hi,
S130 may have something. How hard do you have to press the button?

Does it lock every time? will it lock the car (you can hear the actuators even if it already locked) when it won't unlock it?
I think it is more likely that its either a bad battery or an issue with the key either battery (where did you get the new battery? there are a lot of fakes and old stock out there) or a bad solder joint. Do you only have one key? The car cam with two.
Unfortunatly the Croma CODE security system is complex with the engine ECU, Body computer, key reader, electric steering lock module and keys all coded so you an't change just one easily. It's different to other Fiats too.

There is software called Multiecusan www.multiecuscan.net that with a ELM327 USB interface and a PC can do a lot of diagnostics. If you plan on doing your own maintenence it's pretty much essential.

Where are you located?

Robert G8RPI.
 
Just checked on my latest MES for Croma and the support available is:

Body Computer : TEG Reader TRW (Electonic Key)

Here you can read any applicable error codes and do Key Programming.

WORDS OF STRONG WARNING! Key programming is potentially very dangerous. You can be left with a dead vehicle requiring recovery to a Fiat dealer and potentially requiring expensive module and key replacements.

Please DO NOT play in any key reprograming functions unless you 110% know what you are doing.

However, reading of faults codes and general diagnostics will not be an issues and may shed some light on what is going on.

AGAIN! Do not mess with any key reprogramming/learning!

These key learning/reprogramming functions require the vehicles security PIN code so for most dabblers they will not have the code. But for those that do there is still a very great risk you will kill your car. PLEASE tread very carefully.

If a dealer/other agent screws up then that is their problem and expense to solve. If you do then it can be very expensive!
 
Last edited:
varesecrazy said:
Hi Lee. And welcome to FF.

The Croma wasnt a great seller in the UK.. so many mechanicals are sourced via GM related cars.

That might be a course to pursue..

Of course getting the body computer interrogated..then reset.. could well help also.

Charlie
Click to expand...

Thanks Charlie, interesting point about GM, will look into that.
 
s130 said:
I've never experienced or heard of this on any Croma.

However I had an issue with my 500X similar to yours where one key failed to work and when I tried the other that did as well. Somehow eventually (can't recall the details, but I did use the manual key) I got both keys to work.

My theory/explanation is as follows.

The key/fob/security system uses rolling codes. So on press 1, code X1 is sent. On Press 2 code X2 is sent, and so on. Now clearly key fob keys will get pressed accidentally or when out of range. This means the vehicles security system / key code system has to be able to cater with this and thus will have "look ahead" code sequences that are valid. However this list can not be unlimited so if a key fob key is permanently pressed when out of range of the vehicles key code unit/body computer then the "look ahead" list is exhausted and the transmitted code is deemed invalid.

Now this would be a permanent/hard problem unless there is some form of reset built in or the many hundreds / thousands of codes return back to the seed value (i.e. loop round again).

So my possible explanation / theory is that your key fob is button stuck and continually transmitting codes (or something is) and when you use a physical key to unlock the car the system accepts and resets.

In my case I've had plenty of occurrences where key fobs, my phone in tight trouser pockets has caused unwanted activation.

Can't be sure but worth following up at your end.
Click to expand...

Thanks, thats a good point about the fob, does make some sense as the buttons dont feel the most tactile and feel quite worn.
 
s130 said:
I've never experienced or heard of this on any Croma.

However I had an issue with my 500X similar to yours where one key failed to work and when I tried the other that did as well. Somehow eventually (can't recall the details, but I did use the manual key) I got both keys to work.

My theory/explanation is as follows.

The key/fob/security system uses rolling codes. So on press 1, code X1 is sent. On Press 2 code X2 is sent, and so on. Now clearly key fob keys will get pressed accidentally or when out of range. This means the vehicles security system / key code system has to be able to cater with this and thus will have "look ahead" code sequences that are valid. However this list can not be unlimited so if a key fob key is permanently pressed when out of range of the vehicles key code unit/body computer then the "look ahead" list is exhausted and the transmitted code is deemed invalid.

Now this would be a permanent/hard problem unless there is some form of reset built in or the many hundreds / thousands of codes return back to the seed value (i.e. loop round again).

So my possible explanation / theory is that your key fob is button stuck and continually transmitting codes (or something is) and when you use a physical key to unlock the car the system accepts and resets.

In my case I've had plenty of occurrences where key fobs, my phone in tight trouser pockets has caused unwanted activation.

Can't be sure but worth following up at your end.
Click to expand...


Hi Robert, im based in Liverpool. Unfortunatley I only have one key. Once I have used the key and the fob and car are "awake" , the fob works perfectley with every press of the fob, locking + unlocking correctley, even from distance and I dont have to press hard or anything.Its a bot of a strange one.
 
Magnumwhite1 said:
Hi Robert, im based in Liverpool. Unfortunatley I only have one key. Once I have used the key and the fob and car are "awake" , the fob works perfectley with every press of the fob, locking + unlocking correctley, even from distance and I dont have to press hard or anything.Its a bot of a strange one.
Click to expand...

Apolgies got a bit mixed up there addressing you as Robert, having some problems with my phone, will try downloading the app.
 
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