HV Battery Shut Off - MG4 suddenly died

[HRL]

Yesterday had a weird experience with MG4 Trophy, just under 3 years old. Left on school run as usual and after about 300 yards it suddenly died, no power at all, blocking a road and wouldn't allow being pushed forwards or backwards. Tried a few times to lock/unlock but no change, message on dash was 'HV Battery Shut Off'. Rang MG garage (no help), rang MG Assist and whilst on phone to them got back into car again and messages all gone and it worked as usual and I just drove home again and not dared go out since! Nothing came up on the app (unlike the constant tyre pressure warnings I get in cold weather).
So did it just have a moment and I should ignore and assume all OK now? Or should I take to garage and potentially have to leave it for weeks to be checked? Can garage look at diagnostics online without me going there? Anyone else had this?
Thanks in advance.

 

[ReintjeWA]

I don’t think the dealer can check diagnostics remotely. I would get them to look into it if only to ease your mind a bit.

I had a conrod escape through the side of the block in the RCZ once, even thought the replacement engine was newer it made me hesitant to drive for a good while after. Something like what happened to you can really take the joy out of a vehicle.

 

[ReintjeWA]

Also might want to check out this thread (not sure if it is exactly the same as what happened to you)

E

Thread 'total loss of power on a busy dual carriage way - I'm really scared it will happen again'

Jul 19, 2025

My MG4 Trophy lost all power whilst I was accelerating to get on to a busy dual carriage way on Thursday. It was a hugely scary experience for me & my child as we tried our best to carry out all the correct actions & report the obstruction to emergency services whilst barely being able to hear the operator on the other end of the phone due to the traffic noise. Most drivers seemed to take no notice of my arm waving to slow them, or my red triangle. I sit here now simply relieved that no one was hurt or killed during this incident. Up until now I've loved my MG4 (despite the odd niggle) but...

• Ezza
• carriageway diagnostics emergency services mg4 scared total power loss
• Replies: 35
• Forum: MG4 EV Forum

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[HRL]

Update....so tried car again today, 2 days after first breakdown. Seemed ok and did a few short trips, then suddenly got same messages flash up this evening, complete loss of power again, left it for 10 mins and tried again still no good. Fortunately was in Tesco car park so safe place to leave it and got MG Assist coming tomorrow morning. They assured me that even if it seems to work tomorrow they will follow me to MG Garage. Saying that garage say can't look at it until end of the month, and courtesy car only for 3 days .....mmmmmmmm.
Will post again once got info back from garage as might help others in future.