C5 mk1 facelift problem with remote central locking

[Dommo]

Hi all

I've had a bit of a strange issue with the C5 remote locking today, on the face of it the remote locking stopped working. The first thing I checked was with a spare key, still not working, then I checked the fuse in the car, and while sat in the car it worked.. Great! Or so I thought. I got out of the car and walked away, went to lock it and it stopped working again.

It seems as though it only works when I'm stood right next to the car. Once I move away it stops working again.

Any thoughts here? Is this something simple?

Thanks all, Dom.

[GiveMeABreak]

Battery in the fob sounds the obvious thing given that it's the range of operation that seems to be the issue. Sounds obvious, but when the batteries last changed?

[myglaren]

Are you parked in the same place as before?

I had a similar thing at work. One of the car parks had a mobile phone/communications tower just outside and the remote locking wouldn't work there. Not just my car but not all cars.

May be something similar affecting yours.

[Dommo]

Thanks for the replies guys. I should have said that I’ve checked the batteries in both the original key and the spare key, the original key’s voltage was 2.9-3.0 volts, which seemed a smoking gun but the spare key had 3.2 volts. I put the 3.2v battery into the ‘main’ key and it still didn’t work any differently unfortunately!

I don’t believe there is a mobile mast at fault here but I’m open to all suggestions. The issue wasn’t there at 3pm and then suddenly was there at 5pm, outside my house on the drive. I’ll see how we go on when I go out in it tomorrow.

Thanks again!

[GiveMeABreak]

Try reinitialising the fobs again:

Put the fob into the ignition, switch to ignition on only and press the fob lock button for a few seconds, release and remove fob without starting vehicle, repeat for spare fob.

Then try several locking and unlocking procedures from outside the vehicle.

As a last resort and don't laugh - aiming the fob at the side of your head whilst operating has been known to increase range....

[PaulC5]

I have found with our 2007 C5 if the spare key is not used for some time such as more than a month, it loses initialisation with the car. It can be got back by following the handbook initialisation procedure for its battery replacement but also by using it a lot alternatively with the other remote over a couple of minutes. In your case though you will need to get the first remote working, probably by swapping its battery and then initialising it -probably put it in the ignition, turn it so the dash lights up and press the lock button down for over 10 seconds, then start the car, remove it and then it should work.

When I replaced a remote battery the old one still had full voltage which confused me but with the new one it worked all the time when previously it only worked occasionally to lock the doors.

[Dommo]

Thanks again folks.

Strangely, it is working perfectly this morning with no issues, parked in the exact same spot as yesterday. And interestingly I didn't realise but my partner had issues with her Smart keyfob yesterday, and it worked perfectly this morning too! So it must be a local issue that I honestly never would have expected living where I do...

Another quick question while I'm here, I didn't realise how easy it is to replace the rubber 'buttons' that wear off. I can't however find the correct rubber for my key. I can see a membrane with a boot unlocker button, but not with the headlights symbol, see below:

https://www.ebay.co.uk/itm/391926702240

I imagine this would fit, but I'm intrigued to know if anyone has found the membrane with headlights? And lastly, I did notice on my key circuit board, there is a 4th 'button' that looks like it could be used on some cars, but not mine. Any ideas what this 4th button would be for?

Thanks, Dom.

[Paul-R]

I think the fourtspacr is for vehicles that have a sliding side door. Could be wrong though.

[GiveMeABreak]

That'll be for the C8 and 807 which had a lock and unlock button (top 2 buttons) and 2 additional buttons to operate the left or right electric sliding doors (bottom 2).

New original here:

https://www.car-keys-online.com/genuine ... 90-98.html

Or if you want a used one and have a spare grand lying around:

https://www.ebay.co.uk/itm/264436120876

[Dommo]

That would make sense thanks guys. Unfortunately Marc that key is no longer available by the look of things. I suppose a boot unlocker symbol is not the end of the world for a fiver! Cheers guys

[Paul-R]

Maybe you could get the membrane with the light symbol and then cut that half off? One here quite cheap https://www.ebay.co.uk/itm/303490470247 ... R5im5JzBYw

Possibly worthwhile contacting the seller to see if he can supply the other type?

[dulenator]

If you are not in a hurry, you can always get the part from the country of origin for a cheaper price.
eBay folks don't have the one with the headlight because they source them from China, and they are making only the ones with the open trunk button.

I bought mine from Ali, and it has been working (and still is:)) without any issues for more than two years.

https://www.aliexpress.com/item/1005004 ... ry_from%3A

[Paul-R]

Unfortunately, that has the boot opening logo on the button.

[Dommo]

Maybe you could get the membrane with the light symbol and then cut that half off? One here quite cheap https://www.ebay.co.uk/itm/303490470247 ... R5im5JzBYw

Possibly worthwhile contacting the seller to see if he can supply the other type?

If you see my first post again I put up an eBay link for the boot symbol membrane for a fiver, even cheaper.. in fairness my membrane isn’t too bad now I look at it on the photo above.

[dulenator]

Unfortunately, that has the boot opening logo on the button.

Yep, but it should be cheaper than the eBay variant. I bought three pieces for all my keys since they were all scratched.