Remote unlock issue with heat?
 

Hi there


In the past couple of days the X5 is parked on the sun for the whole day and well, it's hot season.
The problem is that now none of the 3 buttons are working, and that on both keys. Never had issues before. So it's definitely the car not the keys.
Car starts and runs just fine.


Did anyone had a similar issue?

Where is the remote unlock module / antenna located? Could check for melted wires or anything else.

The sync procedure that i've already performed before doesn't work: key in position 1 for a second, remove, keep pressing unlock while pushing 3x on lock, when releasing unlock the doors should lock and unlock to confirm the sync but nothing happens.

Still can lock unlock manually with key in driver's door but who doesn't like to walk away and make it blink from a distance?;)

Thanks

Did you read it for any codes?

Can you go ta key shop and have the fob checked to see if it's transmitting?

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No related codes.
So both keys emitting and car receiving are working.
Something is weird in-between.

Say today i take key 1 for a drive. First none of keys opens the car remotely, sync procedure not working.
I start the car with key 1. When turning the car off and removing from neiman, this key will work to open remotely and sync procedure works. Only for this key, not key 2.
Tomorrow I'll come back to the car, no keys are working, back to beginning...

I really don't get the logic behind that behavior.

The synch procedure can be tricky, especially with 2 keys, but sounds like you might have battery/circuit board issues with the remotes as well.
Are you SURE BOTH keys were working perfectly before?

If I remember correctly the second key gets synched right after the first without doing the ignition cycle again.

How do you know both are transmitting?

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Ok so there is good and bad news.

The good is that one of the keys is now always working, even after a day or 2.
The bad is one of the key coin batteries i recently replaced is now at 1.5v instead of 3.6. So i'm good for another replacement...
I usually switch between both keys each month so they both stay charged. Probably a faulty battery.

That said, i still don't know why the remote / sync completely stopped working for few days.

Removed the plastic trim from the hatch, inspected the EWS FZV amplifier which looked fine, as well as the wires (found a similar post where the power wire of the amplifier snapped in the wiring boot of the hatch)

And yes when you want to sync 2 keys or more, need to put only one in the ignition and then do the buttons procedure for each key one after the other, and fast.

So more to the story and some false assumptions. Obviously both keys were not emitting like you said, and you failed to mention you replaced the battery, probably with a wrong one. Maybe switch the order of the keys when you synch them and see what happens then.

I think it's safe to assume that of them was always emitting because it's working now without opening it. Something was interfering with the whole thing those few days.

Replaced both batteries recently on same time, and the sync worked for both in a row. The solders are good in the faulty one. But with 1.5v no wonder it wasn't syncing properly.

At first thought it did not occur to me that the almost new battery already passed out, so forgot to mention that detail. Can happen with aftermarket items i guess.

The original Sanyo batteries are incredible and hard to get the same quality, so maybe if you still have the old one it might still be good or at least better than what you are replacing with.

When i bought the car one was already replaced, and the other was probably a Sanyo if it's oem. But it was very much out of shape (not working further than 2m distance) even after long drive to charge it.
So now i have no choice than using those crappy yellow batteries you find on ebay, at least with practice it takes me like 5min to change it.

Can you tell me here this plastic trim is on the hatch?

My new OE key I got from BMW just stopped working one day last year. It worked for about 18 months. The central locking button inside works as expected, as does the door lock.

Here you got the exact location.
https://www.bmwgm5.com/Images/FZV/FZV_X5_Location.jpg

Might be also the battery in your case.


Also figured out something, i don't think it created the issue but definitely something to consider for whom want to replace their batteries.

So since i started searching about replacing the batteries of the remote key after buying the car, i found out that the replacement batteries are LIR2025 3.6v.

Except it's not...

Apparently the closest to OEM fit are VL2020 3v.

Should have went further than trusting ebay on search results for "E53 key battery"...

Ordered a couple of those, will keep updated when received and replaced.

Yes, I think that's all posted here somewhere, I think it was the VL2020 that I used years ago and has been good, but I think I remember finding the OE Sanyo purple battery available somewhere afterwards.

Could be, but the fob was new from BMW only about a year before. Tried charging it with a Philips toothbrush charger in case the in-car one wasn't working, but that didn't do anything.

Thanks for the pic. I'll have a look. Maybe a hard slam knocked a wire loose...

Also saw a topic where the power wire was damaged in the rubber boot that's between the hatch and the car