C4 Replacement Fob Not Working

[GiveMeABreak]

Ok so just unlocks the boot. If you have had it working on the 3 button plip, then you know the car is programmed for it - but your plip does not have compatible circuitry, so change supplier and get a decent one maybe.

[Paul-R]

It's possible that it's just a faulty unit. Trouble is that Aliexpress have a less helpful set of rules compared to Ebay. I would suggest that you go back to the supplier and say that it's faulty and see what they offer. You might even be told that you have to pay for return carriage.

You'll have to do it quickly though as there's a much shorter period than you might think. And if you haven't got it sorted before the time runs out then that'll be it.

[Cutac]

I've contacted the seller and he's not responding. All I can do now is leave a negative review since 15 days have passed from receiving the key.

[GiveMeABreak]

I would leave it a while - There are significant time differences - even the Chinese sellers on ebay take 24 hrs to respond to every message - they're always a day behind I find.

[Cutac]

It's already been 72 hours, I've opened a dispute as soon as I realized the key wasn't working.
Ah well, what can I do now...

[GiveMeABreak]

Don't buy from them again! You have very limited rights:

Regarding AliExpress, Quoted from 'The Guardian'

To be blunt, you have few of the consumer rights you enjoy when purchasing from a seller in the EU. You’ve often no legal right to return an item, even if faulty, and while many of the sites you can buy from offer their own protection policies, it’s not the law. What is more, even if you can return an item, the cost of postage may make doing so prohibitively expensive,” he explains.

This is advice from the UK, but may be true in Croatia - so check with your Bank or Credit Card company..... especially the bit in bold that I've highlighted.

Jan Carton from Citizens Advice says there are some rights which come with credit cards and debit cards regardless of whether goods are being bought under UK law. “If you buy something that isn’t as expected, or doesn’t arrive at all, you can contact your credit card company to ask for your money back if you’ve paid more than £100 but less than £30,000. For credit card purchases less than £100, or if you’ve paid by debit card, you may be able to get a refund via the ‘chargeback’ scheme if you request it within 120 days – check with your card provider,” she says.

[Paul-R]

Silly question I know but could the battery in the fob be faulty? Try swapping with the battery in the working fob and see what happens. If working fob keeps working, or not. Whether replacement now syncs, or not.

Ideally an RF spectrum analyser could say for sure whether a signal is even being sent.

[Cutac]

Thanks!
I'll call my bank to see if that can be done!

I'll see if I really want a 3 button key, and if I do, I'll buy it at the dealer. Ill save some money by pairing it myself, but this time, I'll know it's a proper key that will work with my car.

First thing I did was a new battery.
How can RF analyser be obtained or what kind of business uses one?

[Paul-R]

But just to confirm the battery isn't duff try swapping them around. This will provide information that simply plonking a new one in doesn't.

I have a vague recollection that some of the better locksmiths have kit that can determine whether a fob is emitting RF. Apart from that I'm not really sure except that maybe some of the more esoteric SDR (software defined radio) kits might be able to tune down to that frequency. Disconnecting the normal external aerial and just having a small stub next to the keyfob might show something. Frankly I'm just playing a thought experiment with that one. There do exist RF sniffers that the likes of OFCOM use but they're megabucks.

[Cutac]

2 button fob has a different, smaller, battery.

I've a friend who's a kind of expert on car electronics and he told me that it's basically the same - 433 and 434 MHz specification, that it should work nevertheless.

Locksmith who cut my key is specialized in car keys, I'll take this key there for testing, or if he has that kind of key for sale, I'll buy it. Much easier when there's a proper receipt and when I have consumer rights

[Paul-R]

And, of course, the internet knows. Here's using an SDR dongle and your phone.

[GiveMeABreak]

I've a friend who's a kind of expert on car electronics and he told me that it's basically the same - 433 and 434 MHz specification, that it should work nevertheless.

I think I said previously, it’s not just the frequency, it has to be sending the right info too.

[Cutac]

I believe that dongle is not particularly cheap. I'll intall the app, maybe Nokia has that needed hardware

I've been in the Diag right now, went through all the settings and nothing useful. I mean, car definitely supports 3 button key since there are various options regarding 3 button key which are pre-set by factory.
Probably a faulty key...

[Paul-R]

I believe that dongle is not particularly cheap.

Depends what you think is cheap. About £20 I believe.

I'll intall the app, maybe Nokia has that needed hardware

Highly unlikely that it will work but if the app is free give it a go.

Probably a faulty key...

But without checking you won't know for sure.

[Cutac]

20 pounds is a bit too much for one time deal.
And no, Nokia doesn't have supporting hardware.

Anyway, I've already asked GiveMeABreak this question and he told me not to fiddle with this, but, could this somehow be related to the key not working?