If you think putting your car key through the washing machine is bad...

[Rolfe]

It's possible you may be right...

 

[Rolfe]

With a discharge happening within just 3 days, my finger-in-the-air guess is a short, possible within one of the buttons, that is causing the fob to continually transmit and run the battery down. A close visual inspection with a jeweller's eyeglass may turn up something, but I don't hold out much hope.

I've taken the thing completely apart and it's pretty simple inside. Just a PCB populated on both sides, clipped into a clear plastic holder that incorporates three plastic "button" tabs that are depressed on top of the three contacts on the PCB by pressing the relevant part of the case, which is flexible enough to operate these tabs.

I don't see any sign that there has been water in there (the fob as such didn't come apart on the road, although the emergency key fell out) and the PCB looks fine to me. If it isn't I'm screwed, but I don't see how it could have been damaged by what happened.

Based on Everest's speculation, I think possibly that the plastic tabs, or maybe just the middle one, have been bent down towards the contacts by the weight of the vehicles that ran over the fob. I have been able to bend them back up again so that they're sitting proud and not coming into contact with the contacts unless the fob is pressed.

I'm prepared to sacrifice another battery to see if this does the trick anyway. I'll keep you posted.

 

[DixieTGS]

If you could actually see the problem that matches the symptoms, it'll probably be good to go after your testing. I'm not sure if the possibility of PCB damage as well would still niggle away at me though, and I'd end up replacing it anyway.

Do you have a Bluetooth key setup just in case?

 

[Everest]

I'm prepared to sacrifice another battery to see if this does the trick anyway. I'll keep you posted.

def worth a try.... being only about 40-50p each (if you buy them in packs of 6-10 for the moggy). PCB looks pretty simple too.

 

[Rolfe]

When I disassembled the fob it looked as if the plastic tabs might have been forced down against the terminals so that the middle one at least was in contact with the terminal. If that was the case it would fit with what Everest suggested, that there was a constant drain on the battery. I can always keep this one as the spare key and use the one that wasn't damaged day-to-day. It's all working again with another battery so I''ll just leave it for a few days and see what happens. Yes, the batteries are cheap and I have to keep a stock of them anyway.

When I try the "keyless start" in the app it tells me to connect the Bluetooth and try again, even though I think I have connected the Bluetooth. Maybe I need to pair it again or something?

 

[DixieTGS]

When I try the "keyless start" in the app it tells me to connect the Bluetooth and try again, even though I think I have connected the Bluetooth. Maybe I need to pair it again or something?

Hmmm, did the SE SR ever support the Bluetooth key I wonder. My SE LR does, but the latest SE versions apparently don't have it according to the MG website.

The Bluetooth key doesn't seem to need pairing (Bluetooth LE?).

On Android iSmart, if the little Bluetooth symbol on the main page is dark blue, and you previously enabled it, then it should work. To make it try and connect when near the car, sometimes reopening the app works. Otherwise try the connect button on the Digital key page.

Once you get it connected, pressing keyless start allows the car to see the key for 'a while' and you can start and drive the car. I think that any Bluetooth or phone problem is not noticed until you next try to start the car.

It all feels a bit iffy for me to use it as my main key though.

 

[Rolfe]

My SE is a phase 1, bought in early 2023. I just never bothered setting it up.

 

[siteguru]

Hmmm, did the SE SR ever support the Bluetooth key I wonder. My SE LR does, but the latest SE versions apparently don't have it according to the MG website.

The SE (of either variant) has never officially supported the Digital Key (which as you correctly state uses Bluetooth LE, so is separate from the normal BT connection), but mine worked last time I tried it.

You have to go through the process of setting up the Digital Key first though (which involves waving the phone in a figure 8 in front of the steering wheel as I recall).

 

[Rolfe]

I have never done such a thing. Do you have a link to the full instructions?

 

[MG Clive]

The new battery you tried might just have been dodgy @Rolfe, it might be worth trying another new one, or the one from the other fob, which you know is a good one.

 

[salty]

You have to go through the process of setting up the Digital Key first though (which involves waving the phone in a figure 8 in front of the steering wheel as I recall).

Really? Is this a wind up? I can imagine someone sat in there car, frantically waving there phone, in a figure eight, at the steering wheel. Knock on the window, can you blow into this ,please Sir.

 

[DixieTGS]

I have never done such a thing. Do you have a link to the full instructions?

It's a long time since I did it, but I think the only instructions are on the app on the first time you try and use it. On the app version I used you only had to hold it near the centre of the steering wheel, but they may have changed it again by now.

 

[OriginalBigAl]

Really? Is this a wind up? I can imagine someone sat in there car, frantically waving there phone, in a figure eight, at the steering wheel. Knock on the window, can you blow into this ,please Sir.

If it does not work first time, try again, don't be de-theta by it.

 

[siteguru]

I may be conflating 2 things - digital key in the car and a compass app on the phone - as regards the "figure 8". But "hold it near the centre of the steering wheel" sounds familiar. The main point is that you need to enable the digital key first before you can use it. The app tells you what to do as I recall.

 

[Rolfe]

Any idea where I might find that? All I'm getting is an instruction to connect the Bluetooth before I can use it.

 

[siteguru]

In the app on the home screen click on the Digital Key section. If a DK is already established then it should appear under there as My Car Key. If there's nothing there then there should be an option to create one ... unless MG's servers have now disabled that feature for SE cars.

(It's over 2.5 years since I did it, so my memory of it is rusty).

 

[Rolfe]

It's odd that they wouldn't have removed the button entirely, if they disabled it.

 

[decrep]

regarding the pushed in button. That sounds very much like the problem.
My worry now is, if you depress the button does it pop back out now?
If it doesn't you aren't out of the woods.

Remote door and start, work with my aussie excite 51.
Just tried it to make sure, but there is an MG quirk in there, once I've unlocked the door, it wont lock the car until I exit and reenter the app

 

[Coulomb]

I think it's worth some DIY as replacement fobs are quite expensive. Mainly because the two fobs have to be re-paired to the car for security reasons. So that makes the gadget that does the pairing special and expensive. It's spawned an entire industry.

That way, only the more organised car thieves can afford to get or make a pairing machine, while ordinary owners pay the price for replacement keys

 

[Ian Key]

I think it's the clear plastic piece being deformed that has caused the battery to drain too especially as the key seems to work OK otherwise. If it was the circuit board in my opinion it would either work or it wouldn't. (I'm sure @Everest will correct me )

You can get just the shell including the clear plastic bit from AliExpress for about £6 and use the original circuit board and physical key.

NH KEY 3-Tasten-Ersatz-Autoschlüsselgehäuse mit hoher Qualität für MG MG4 MG5 MG6 MG ZS EV HS EHS ZX GT - AliExpress 34