New MG4 Trophy LR Vehicle Control System Fault

I'd be making a fuss about getting a different vehicle personally (as in a different MG4 from the dealers stock).

The fault happened on the day you took delivery. If the fault had happened while it was still on the forecourt it'd be reasonable for you to walk away from it and ask for a different vehicle.

The fault in question can have a number of different root causes. If they haven't fixed it after replacing one module you're looking down the barrel of potentially an extended period of troubleshooting through processes of elimination, and then there's always going to be the niggling worry that you got a Friday car and there are other issues waiting to be discovered.

If the car was a few months older, sure that'd be annoying but you'd realistically have to accept trying to fix the vehicle you have. For a car fresh off the forecourt, no. Good customer service dictates they should replace it, in my opinion

Did you check for a loose 12V battery terminal? It's something to do with how they are transported, and is supposed to be checked during pre-delivery.

Coulomb said:

Did you check for a loose 12V battery terminal? It's something to do with how they are transported, and is supposed to be checked during pre-delivery.

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I didn't, check anything, just returned it, I didn't want any chance they could blame me for any issue.

AlC said:

I'd be making a fuss about getting a different vehicle personally (as in a different MG4 from the dealers stock).

The fault happened on the day you took delivery. If the fault had happened while it was still on the forecourt it'd be reasonable for you to walk away from it and ask for a different vehicle.

The fault in question can have a number of different root causes. If they haven't fixed it after replacing one module you're looking down the barrel of potentially an extended period of troubleshooting through processes of elimination, and then there's always going to be the niggling worry that you got a Friday car and there are other issues waiting to be discovered.

If the car was a few months older, sure that'd be annoying but you'd realistically have to accept trying to fix the vehicle you have. For a car fresh off the forecourt, no. Good customer service dictates they should replace it, in my opinion

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I'm going to call in to the dealer today to discuss getting a replacement new vehicle, and they can pay for changes to insurance, etc too.

As you have afforded them the opportunity to repair the goods, and the goods still do not conform to contract, you can lawfully exercise your Final Right to Reject per section 24(5)(a) of the Consumer Rights Act 2015. And as the time of your ownership is negligible then you are entitled to a full refund (or replacement if you both agree).

Got the car back today, a software update apparently was all that was required. I've had a longer drive in it today and no reoccurring issue so hopefully this is it sorted out.

They have said go straight back if it happens again, in which case I'd be less patient...

I had this same problem on my SE after using a home charger.
Fault came and went just like yours. Cured by disconnecting the battery negative terminal for a while, then reconnecting (10mm spanner required). Various faults will show up when restarting but all will clear automatically. No problems since. I suspect the dealer did exactly that! Equivalent to "Turn it off and back on again". Highly recommend that all MG4 owners keep a 10mm spanner in the car.

Had identical fault on way home after picking my car up from the dealer. They reloaded software, been fine since.

New (18 inch wheeled} MG4 Trophy LR, picked up 7 March 25

10 March 25 Intelligent Speed Assistant stuck at 40 MPH [thought it was the low sun] same on the way home - cleared next morning.
13 March 25 Had a Vehicle control system fault after its first charge in my ownership [ to 100%] - but cleared on its own after a few seconds.
14 March 25 - Car Not used
15 March 25 - Intelligent Speed Assistant stuck at 40 MPH, 10 mins later a Vehicle Control System Fault appeared, then a Camera module failure warning, then a few mins later ACC failure. Faults wouldn't clear when powered down or left for hours. Booked into MG Service
16 March 25 - Charge kept stopping -Vehicle Control System Fault & Camera module failure warnings came up and caused the charge to stop.
17 March 25 - No faults in the morning and on the way to MG Service after work.
18 March 25 MG Service updated the firmware on various modules and during one of the updates it failed/crashed and now the Infotainment system won't come on and they can no longer communicate with the car to retry the firmware update.
19 March 25 - Waiting for MG Techs to review issue and advise on fix
20 March 25 - Still waiting.
Anyone had the same issue ?

My wife has just had this exact issue on her week old Trophy…

Vehicle Control System Fault​

Typical that the error appears on a Friday evening. Have done the 12V disconnect - didn’t work, and the biggest issue with the error is it shuts off the HV, so it won’t charge.

Assume next step is the dealer?

@figgles - did you have any further issues after your software fix?

Diggsy said:

My wife has just had this exact issue on her week old Trophy…

Vehicle Control System Fault​

Typical that the error appears on a Friday evening. Have done the 12v disconnect - didn’t work, and the biggest issue with the error is it shuts off the HV, so it won’t charge.

Assume next step is the dealer?

@figgles - did you have any further issues after your software fix?

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Just following up on this - spoke to dealer(s) today, their suggestions (both of them)…call MG Assist.

Seems a poor resolution for such a catastrophic failure on an 8 day old car, but what do I know…I was thinking they’d just say to bring it in on Monday and they’d get it sorted and give a courtesy car, but apparently I have to go through MG Assist for that.

Clearly customer service isn’t what it once was…

You could try just charging the 12V battery with an ordinary car battery charger. "New" cars could have spent a long time in storage or transport, possibly damaging the auxiliary battery. A bad auxiliary battery can cause all sorts of faults.

This sort of problem was common around Covid, but presumably no MG4s are affected by that.

I also assume that you would have noticed a loose connection on the battery terminals. They put some gizmo on the auxiliary battery during transport, and sometimes when that is removed, the terminals are not tightened. It should be checked as part of the pre-delivery inspection, but seems to get overlooked more often than you'd hope.

Coulomb said:

You could try just charging the 12V battery with an ordinary car battery charger. "New" cars could have spent a long time in storage or transport, possibly damaging the auxiliary battery. A bad auxiliary battery can cause all sorts of faults.

This sort of problem was common around Covid, but presumably no MG4s are affected by that.

I also assume that you would have noticed a loose connection on the battery terminals. They put some gizmo on the auxiliary battery during transport, and sometimes when that is removed, the terminals are not tightened. It should be checked as part of the pre-delivery inspection, but seems to get overlooked more often than you'd hope.

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Thanks. I’ll maybe give that a go if I can borrow a charger today. The 12V connections were good when I decided to remove the negative - certainly didn’t seem loose in any way, but I’ll double check that as well.

Just very frustrating for such an issue to occur on a brand new car, and the proposed remedy isn’t the most ideal either.

Diggsy said:

Thanks. I’ll maybe give that a go if I can borrow a charger today. The 12v connections were good when I decided to remove the negative - certainly didn’t seem loose in any way, but I’ll double check that as well.

Just very frustrating for such an issue to occur on a brand new car, and the proposed remedy isn’t the most ideal either.

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Just to update…Had MG Assist (AA) out today - fault was initially showing, then went for a drive with AA following…fault cleared and now charging without issue…here’s hoping it was nothing more than a software gremlin!

Will try it over the coming days and if it happens again, will be back on the phone to have it sorted

…as a further update - still charging. Let it charge to 100% and balancing, which is taking an absolute age and seems very sporadic to me, continually charging for a brief duration at a random speed then stopping and starting again random times later. My SE doesn’t do this, it just lowers the speed and continues until balanced. Starting to wonder if the battery was ever properly charged before delivery…hmm

Diggsy said:

Let it charge to 100% and balancing, which is taking an absolute age and seems very sporadic to me,

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It sounds like it hasn't been properly balanced, which I think is understandable for a new vehicle. But that obviously should not trigger a Vehicle Control System fault.

Coulomb said:

It sounds like it hasn't been properly balanced, which I think is understandable for a new vehicle. But that obviously should not trigger a Vehicle Control System fault.

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Thanks. No idea what has caused that error. Hopefully nothing other than a software gremlin, but time will tell…