A cautionary tale for MG 4 EV owners

[goose]

This really happened and I have proof that all I say is true:

So, I drive an MG 4 Trophy Long Range bought new in 2023.

While staying for a few days in Harrogate, in particular to attend the flower show, the following happened to me and my wife.
After the show had completed I decided to drive to a nearby charge point and top up the battery but, and this is relevant, prior to driving to Harrogate my Smart app stopped working for me. I tried all the usual methods to get around this 'glitch' - none worked. But I figured that was not too great a problem.

So, having found a charge station close to the show, off we went. However, the charge station was on the ground floor of a multi storey car park and it was a Sunday (the day is important too so please bear with me). The car park closes and is locked at 7pm, but I figured, no problem, an hour to an hour and a half charge would be more than enough to get home with 20% charge remaining. We parked up and I attached the charge cable without issue and initiated the charge, it was then about 5pm and all was well. We stayed in the car and ate some sandwiches as everywhere close by was closed. At around 6:15ish I terminated the charge, stowed the cable and made ready to travel back to our hotel. I should point out that in the hotel was all our travel stuff including medication (now the medication is very important as my wife has a number of ailments which require continuous medication).

Then the problems started!

The car would not make ready and would not move. I tried locking and unlocking it a few times. I tried the windows up and down all seemed well, but still it would not come ready and definitely would not move. In desperation and knowing the clock was ticking, I phoned the rescue service. After describing my predicament they placed a response as high priority. Meanwhile I got hold of the building security service and let them know what was happening. They informed me that they had to lock up at 7pm but gave me a number to ring their local chap who would come and open up once the AA arrived and let them in.

I thought maybe it was the 12 volt battery, so as I have a power pack, I attached it but the charge was OK and it didn't need a boost.

Well, the security man (who was on his first day in the job) and I tried everything we could think of to start the car but all to no avail.

The building was locked at 7pm and we had to leave as staying was a health and safety risk. However, by now the windows were down and wouldn't go back up and the doors would no longer lock. So we were faced with leaving an unlocked vehicle all night (albeit in a gated car park) which left me feeling very uncomfortable.

Stuck, well and truly stuck, I was starting to doubt my choice of 'going electric'. Then the AA arrived. We were all (the AA man and his van, my wife, me and the security man) allowed back in and the rescue service went to work!
To cut an even longer story short, he disconnected the 12 Volt battery and left it for a few minutes, meanwhile he took my car keys back to his van and charged the battery.
Upon his return he reconnected the 12volt battery and tried the key - IT WORKED, yippee!
He checked the battery he had removed from the key. A 3volt battery it read 2.99volts (I kid you not) !

So a car full of really expensive and complex systems had been brought to this sorry state by a simple cheap everyday CR032 battery in a car key!!
No warning, nothing to indicate an issue and here I am in this terrible situation, to say I was gobsmacked doesn't come anywhere near.

Now remember the Ismart issue I share at the start. Well this being unavailable prevented me from using that method to overcome the problem.

I have had a great number of cars over the years, some for over 4 years and have NEVER had to replace a car key battery in my life (have I been lucky?)

Lessons learned

1. If travelling anywhere or anytime ALWAYS keep a cheap CR032 battery in your car.
2. Consider carrying your spare key if on a long journey away from home
3. Never ever go into a charge facility where there exists a time constraint - make sure you have 24 hour access 7 days per week
4. Always make sure you have breakdown assist
5. Think about carrying a spanner which will fit the negative pole of your 12v battery - disconnecting it resets your software system I am told
6. If you can, carry a 12v power pack to jump start your car - it didn't help me in this case but it does provide some reassurance.

Sorry for the length but honestly I have missed quite a lot out.

Happy motoring

 

[salty]

So if you had, had a 10mm spanner, could you have saved all that hassle? After reading posts on here, I always carry one. And after reading your post, I'm glad I do. Still not a pleasant experience for you and your Wife.

 

[Bam Bam]

Sounds like a painful and stressful experience.

But have I got this right...

The battery in your key fob was low, which meant you could get into the car but not drive it?

Or were there several problems which coincided together?

How annoying that it didn't just say 'key not detected' or something.

Would it have worked if you'd have placed the key in the bottom of the central console bin?

 

[Alb]

Can't speak for the MG4 but in my MG5, the car warns you when the keyfob battery is getting low.

 

[goose]

Sounds like a painful and stressful experience.

But have I got this right...

The battery in your key fob was low, which meant you could get into the car but not drive it?

Or were there several problems which coincided together?

How annoying that it didn't just say 'key not detected' or something.

Would it have worked if you'd have placed the key in the bottom of the central console bin?

Yes, you are correct, I could get into the car but not drive it. I did get a message that indicated that the key could not be detected and to move it to the bottom of the console bin when I tried to move off, but I did that and it still didn't work. So all this technology and the car is rendered useless for the sake of a simple key fob battery. And, there is no indication in the MG4 warning of a low battery in the key fob.
Sad isn't it.

 

[goose]

So if you had, had a 10mm spanner, could you have saved all that hassle? After reading posts on here, I always carry one. And after reading your post, I'm glad I do. Still not a pleasant experience for you and your Wife.

As it happens disconnecting the 12V battery in this case would have made no difference as it was the key fob battery to blame. That said, I think you are wise to carry the spanner as it is your only option to do a hardware reset if all else fails for other faults. But do get hold of a new CR2032 battery ....just in case.

Edit moderator: CR032 -> CR2032.

 

[fnegroni]

Did the app not work at all or simply not connect to the servers?
If you configure the Bluetooth key in the app, in the future you simply switch off the cellular network on your phone and the app will still be able to use the Bluetooth key to both lock/unlock and to start the car.

 

[decrep]

Hmmm, I'm not convinced, the fob battery read 2.99v. That should at least have worked in the emergency position.
I suspect it was the reconnection of the 12v battery that did the trick.

 

[JonnyG]

Good advice ......... and I do most of that already apart from the spanner !!

You were certainly unlucky with the timing and circumstances of it all

For 1, I keep the spare CR2032 fob battery in my pockets / wallet / bag near my keys, as a fully depleted fob battery probably won't let you into the car at all. Using the mechanical key can be a little tricky, expecially in a tight car park away from home.

 

[slmorgan42]

So if you had, had a 10mm spanner, could you have saved all that hassle? After reading posts on here, I always carry one. And after reading your post, I'm glad I do. Still not a pleasant experience for you and your Wife.

lol I got mine before I got the car

 

[Martinonline]

There is an interesting video about the consequences of an unrecognised keyfob battery failure on a 150k Lotus undergoing a review by 'Dadcars'. At

 

[Kithmo]

I had the same issue with my ZS back in 2021 when a pod point AC charger timed out and cut the power before I had chance to confirm the charge (my fault for taking so long). Luckily I had read about the disconnect the 12v trick before and had my trusty 10mm with me. I didn't think the MG4 was as susceptible to this problem, but I still carry my 10mm in the glove box, just in case, along with my 12v booster.

 

[Tuareg]

Can happen to any car that is keyless, nothing to do with MG or an EV.

 

[goose]

Sorry everyone and, for the eagle eyed members around, the key fob battery is in fact the CR2032, I missed the first 2 from my post so please don't go looking for the incorrect battery number I quoted,
It is the CR2032.
Hope I didn't cause too much confusion

 

[goose]

Did the app not work at all or simply not connect to the servers?
If you configure the Bluetooth key in the app, in the future you simply switch off the cellular network on your phone and the app will still be able to use the Bluetooth key to both lock/unlock and to start the car.

Well at first I was able to lock and unlock the car until it eventually wouldn't even do that and reported that I should try again later (which I did for a number of days). Strangely it also defaulted to metric rather than imperial measurement without any input from me. I have to admit I was confused by the whole thing but decided that as in the past it would right itself eventually.
I love your suggestion with regard to configuring the bluetooth key but unfortunately I haven't a clue how to do that. Are there instructions somewhere that I can access?
It would certainly be another 'string to the bow'
and thanks for your help.

 

[EvTek23]

I'm with @decrep with this one.
I believe the battery in the keyfob is only responsible for the remote locking and unlocking functions of the car by 433MHz RF technology. The part which communicates with the car to allow it to start up is RFID technology based. There are antennas in each of the front door handles, in the rear hatch lid, and the emergency position in the bottom of the armrest centre console. When you approach the car and press the button on the doorhandle the RFID part of the keyfob is energised by the car and negotiates with the keyfob to determine if it is the correct one. Once sat in the car it is continually communicating its presence with the car. If it doesn't then the No Smartkey Detected message is displayed. The system is essentially passive, in that it has no battery but gains enough energy from the antennas on the car to be able to communicate with the car. The buttons on the keyfob when pressed emit RF at 433MHz and is received by the car by a different system to allow the doors to be unlocked.
The system in the Lotus Eletre is somewhat different. The car is provided with key cards and the keyfob (pebble). The key cards are RFID and work by holding them against the door B pillar, while the pebble is a Bluetooth device which has a power saving mode to extend battery life. This comes out of power saving mode when it comes into range of the car, and explains why some users have experienced only a few months life from the battery with the Lotus. In the context of the MG it is not comparing like with like.
There were a number of simultaneous and unfortunate events happening with the post @goose made.
This is my understanding of how the systems work by the research that I have carried out.