Technical Fiat 2.8JTD Starting issue ..keys from two different vehicles on the same bunch ? (1

[scotjimland1]

I had a message form a member about this problem, but thought for a wider audience and may be useful info ..

Can having ignition keys from two different vehicles on the same bunch cause an issue with starting ?

Yesterday the van just cranked over, usually it starts on first turn of the key.. tried a few times , then it started

When out shopping and it did it again.. twice..

Plenty of fuel, but then I wondered, did having my daughters car key on the same bunch cause a problem?

I tried googling this without a definitive answer ..

I have removed her car key and tried starting several times with no problems.. but still unsure if that is the problem..

 

[The Panda Nut]

I regularly have two or three sets of keys in the Pandas when garaging them, and have had them on the same bunch on occasion and it has no impact for me. It should surely just ask for a matching code and start if its there. Any other keys near should be irrelevant I suppose.

 

[Reg 65]

There is a coil around the ignition key barrel which communicates with the key wirelessly like those security tags in shops which set off the alarm if taken past the exit
So I can well imagine it communicating with the wrong key
(incidentally that coil is wired to the ECU - putting a secret switch in the wire makes a good anti theft device)
If its not communicating with right key it shows the padlock light on the dashboard on the X2/50 and later models - don't know about pre 2006 models

 

[bugsymike]

It is always good advice not to have chipped keys for other vehicles on the same key ring in close proximity to the "aerial ring" around the ignition lock in case it confuses the signal. Some are more sensitive than others.

 

[Communicator]

There is a coil around the ignition key barrel which communicates with the key wirelessly like those security tags in shops which set off the alarm if taken past the exit
So I can well imagine it communicating with the wrong key

My current understanding is that when the ignition is switched on, a radio signal is used to supply power to the key. In effect a non specific challenge, to which any key within the limited range may respond with its code. If the received code matches one stored in the vehicle, the key is recognised. From eLearn, at the same time the ECU sends a code to the code recognition device, which returns the code only if the key has been recognised. If the code is repeated back, then injection of fuel is allowed. This latter code is described as a rolling code, which I assume means that it changes at every start. If two keys are within range, I agree that the second key could corrupt the code transmitted by the first key.

(incidentally that coil is wired to the ECU - putting a secret switch in the wire makes a good anti theft device)
If its not communicating with right key it shows the padlock light on the dashboard on the X2/50 and later models - don't know about pre 2006 models

With the x230, and the x244, there is a dedicated code receiver in the steering column. With the x250 and x290, my understanding is that the code receiver function is embodied BCM. Hence my use above, of the term "code recognition device".

 

[scotjimland1]

thanks for all the help and good advice..

with your permission I will pass on the to members on MHF ..

James