MY2018 cars

[Lexman8]

Yes, you get a warning on the driver's display. The battery is a CR2032.

Not seen any reports of one being replaced yet.

[neon]

Originally Posted by Torshen

Cheers. Does the car give you a warning message when the key's battery is getting low so you know to replace? Has anyone had a key battery die yet? I assume they're CR2032's or similar, are they?

/goes to check manual

I would think it is part of the annual service to change the battery. I think that is what Mercedes does. Obviously only the key fob that is taken in when servicing.

Thanks Lexman for the info on the key fob battery being flat and what to do, was not aware of that.

[Lexman8]

Originally Posted by neon

I would think it is part of the annual service to change the battery. I think that is what Mercedes does.

That's what Lexus does.

[John Laidlaw]

Mercedes do it on a B Service I think only (every two years) but I need to check that!

[neon]

I have never had keyless before so not sure if the batteries need replacing more often. Also do they store data that could be lost if the battery is not changed quickly enough.

[Torshen]

While we're on the subject of keys I've got another quick question that's not worth its own thread.

Is it possible to lock keys in the car and be denied entry? On my old XC60 I'm pretty sure it's simply impossible to lock it at all if there's a key in the car. But on the 90 I think I locked it the other day using my key while my wife's handbag (with her key inside) was in the boot.

I would assume that there's some logic that would prevent me from locking the car if the key that was currently 'active' (IE being read wirelessly by the transceiver) was determined to be inside the vehicle, but is that true?

So for example, if I left my key in the centre console and tried to lock using the touch buttons on the doors I guess it wouldn't let me, right? Might have a quick test later with the wife's key out of range indoors.

[Lexman8]

With one key inside the car, another key outside can be used to lock the car. The inside key is then disabled so that if someone breaks into the car they cannot use that key. The inside key becomes active again when the car is unlocked using the outside key.

In theory, it's not possible to leave a key in the car and then lock yourself out by using the lock button on a handle. However, it has happened to someone on here, possibly because the key's location was sensed incorrectly, i.e. the car thought it was outside when it wasn't. These cars use only 3 antennas plus the backup reader to work out where the key is so incorrect location sensing is possible. (My previous Merc had 6 or 7 antennas to accurately determine where the key was.) Putting a key in the cup holder should mean the car senses its location correctly but I wouldn't rely on it.

[John Laidlaw]

Yes, I was given the 'activity' key yesterday and the explanation was that I could lock my other keys in the car safe in the knowledge I can use this small and indestructible activity key.....

[Torshen]

Originally Posted by John Laidlaw

Yes, I was given the 'activity' key yesterday and the explanation was that I could lock my other keys in the car safe in the knowledge I can use this small and indestructible activity key.....

If you have it with you, otherwise it's a cab home and back. But I guess it's still good to have.

Incidentally, and I guess this probably isn't unique to MY18, but I was quite impressed with the presentation box the keys come in... I've no idea what to do with it now, mind, since both keys are in regular use and don't live in that box anymore, but it was still a nice touch.

[John Laidlaw]

Originally Posted by Torshen

If you have it with you, otherwise it's a cab home and back. But I guess it's still good to have.

Incidentally, and I guess this probably isn't unique to MY18, but I was quite impressed with the presentation box the keys come in... I've no idea what to do with it now, mind, since both keys are in regular use and don't live in that box anymore, but it was still a nice touch.

Yeah did like the box, nice touch as you say - when you say both keys in regular use - have you set profiles linked to the keys on each? Been thinking of doing that....