C5 Aircross Key Fob Problem

[mikehemmins]

Hi. So, I've changed the battery in one of the keyless entry fobs for my 2021 Aircross, but I can't get the car to fully recognise it. I say 'fully', as I can place the fob against the backup recess on the side of the steering column and the car will start and stop that way, but when I take the fob of the recess, the car can't recognise a key. The manual says hold against the steering column and turn on/off which I've done but still can't get full functionality.

Any thoughts would be gratefully appreciated. Thanks in advance...

[GiveMeABreak]

Not sure I understand what you're saying - you say you can start the car, but then you say "but when I take the fob of the recess, the car can't recognise a key."? This I assume is Hands Free, so what is the problem - what is not recognised?

Please be specific. Are you saying you can't use the fob to use the remote locking and unlocking?

Get in the car, place gear in neutral and depress clutch if manual, place fob and hold it against the backup panel on the steering column and press the stop start button until the ignition comes on, to reinitialise it.

After this, switch off the ignition and press and unlock the open and lock buttons several times to see if this has worked.

[mikehemmins]

Yes. You have stated the problem. The key fob will not work to open the door or turn the car on/off unless pressed into the recess in the steering column. Take the fob off the recess and it becomes effectively useless. Not sure how else I can explain it. Sorry

[GiveMeABreak]

Ok, so there is a recognition issue - have you got the same problem with the spare fob or is this the same? If the spare works, then you may have a damaged fob - typically if these are dropped they can damage the circuitry and that may be why the remote functions are not working.

When you hold the key near the backup panel, it energises and communicates with the transponder chip in the fob directly. This is why it will allow the vehicle to be started and unlock the steering wheel. But if the internals are damaged from a drop for example, then the remote element or the sending signal from the fob may not be working - this will be so if you cannot open the door using the hands-free door handle - which means the fob is not sending the signal to the hands-free aerials and to the hands-free unit.

If the other spare fob works, then you have likely damaged the fob that is not working - and may be why you thought it was the battery in the first place.

[mikehemmins]

OK thanks. This is the spare fob and all I’ve done is change the battery. I had thought it may be damaged but given it part works I discounted that. Anyway, no worries I’ll have another go. Thanks again

[GiveMeABreak]

So bear in mind what I said - there are separate functions of these - the fob transmits a signal when being carried or in general use - if it's damaged it won't transmit so there will be no signal to pick up by the vehicle aerials dotted about the vehicle. Failure of this will prevent hands-free entry and hands free starting, requiring the backup mode use to start the vehicle.

The remote locking and unlocking functions using the fob buttons are separate again.

Then there's the integrated mechanical key for emergency locking and opening.