2 month old ZS EV LR - several faults and now HV Battery Shut Off

Since buying my MG ZS EV late February I've had minor faults appear on I would say 3 out of every 4 journeys. They don't stop me using the car but they stop ACC from functioning.

  • Auto Emergency Braking System Unavailable
  • Pedestrian Auto Emergency Braking Unavailable
  • Vehicle Control System Fault
Not very worrying as I say. However today the car shut down completely mid journey with ...

  • HV Battery Shut Off
Fortunately the car stopped in a relatively safe place - Christ knows what would happen if that was on a motorway! Several attempts to restart the car failed, taking it through stop, lock, wait, unlock, start (foot firmly on brake). RAC were called out and the guy was able to get it going by ...

  • Plug in computer to car port
  • Check and clear all faults
  • Remove negative terminal from battery
  • Wait 10 minutes
  • Reattach negative terminal
  • Restart car normally
Since the above I haven't had a reoccurence of the minor errors but we'll see what happens over the coming days. The car is booked into my local MG dealer in May to investigate the minor faults. Needless to say this has shaken my confidence in the MG. I hate to imagine my wife using the car by herself on the motorway and the HV battery shutting off, bringing the car to a fault.

Has anyone else had this issue? I will contact the dealer tomorrow and get their advice, but I want to know what caused this and whether it's likely to happen again.
Hello
Buy a 10 mm spanner to remove the negative terminal. Had to do this once in the middle of France at 2am as I had plugged in with the car still on 😮
 
Since buying my MG ZS EV late February I've had minor faults appear on I would say 3 out of every 4 journeys. They don't stop me using the car but they stop ACC from functioning.

  • Auto Emergency Braking System Unavailable
  • Pedestrian Auto Emergency Braking Unavailable
  • Vehicle Control System Fault
Not very worrying as I say. However today the car shut down completely mid journey with ...

  • HV Battery Shut Off
Fortunately the car stopped in a relatively safe place - Christ knows what would happen if that was on a motorway! Several attempts to restart the car failed, taking it through stop, lock, wait, unlock, start (foot firmly on brake). RAC were called out and the guy was able to get it going by ...

  • Plug in computer to car port
  • Check and clear all faults
  • Remove negative terminal from battery
  • Wait 10 minutes
  • Reattach negative terminal
  • Restart car normally
Since the above I haven't had a reoccurence of the minor errors but we'll see what happens over the coming days. The car is booked into my local MG dealer in May to investigate the minor faults. Needless to say this has shaken my confidence in the MG. I hate to imagine my wife using the car by herself on the motorway and the HV battery shutting off, bringing the car to a fault.

Has anyone else had this issue? I will contact the dealer tomorrow and get their advice, but I want to know what caused this and whether it's likely to happen again.
I've had my ZS EV since June 23 and after the RAC showed me the remove negative lead reset, I carried a 10mm spanner in the door pocket and used the "trick" approx every 3 months and makes the car feel like new again.
Problems I've had and all fixed with neg lead reset.
Unable to reverse if car is forward on an incline. (This was first that prompted call to RAC)
Regen braking mode 3 not working.
Strange problems of car keeps braking with nothing around (sensors all clean)
Random ICE not working and Home button reset not working
Door / lock /unlock madness.

My partner refuses to drive my car because of this. Her Honda has none of this nonsense.
 
Hello
Buy a 10 mm spanner to remove the negative terminal. Had to do this once in the middle of France at 2am as I had plugged in with the car still on 😮
Yes I've put one in the car.

Good to have this as an emergency action, but to me it's not acceptable for a brand new car to have these issues. We should not be simply tutting and saying "it's the computer what can you do".
 
My partner refuses to drive my car because of this
You need the official MG accessory then...

1745093145371.webp
 
Not good news really. I picked up the car today, to be told they could not find or fix anything because there were no error codes.

The first battery death event, the RAC cleared the codes. I gave the service desk the printout but they claimed this wasn't enough.

The second battery death event, no error codes were cleared. So service area basically saying there were no error codes relating to this?

So basically I have a working car back, but nothing's been done and therefore I'm waiting for it to happen again.

Service manager wasn't in today. I've asked for him to call me tomorrow. I'm not happy. It's not good enough.
 
Tracing computer faults, if the computer crashes before it can write the codes is almost impossible. Even with a running log of all computer activity, it can suddenly end at different places every time it happens.
The mechanics at the garage have no hope.
Intermittent problems are the worst. You need tracers on suspect areas to see what happens when it crashes.
 
The second battery death event, no error codes were cleared. So service area basically saying there were no error codes relating to this?

So basically I have a working car back, but nothing's been done and therefore I'm waiting for it to happen again.

Service manager wasn't in today. I've asked for him to call me tomorrow. I'm not happy. It's not good enough.
Doesn't make sense there were no error codes at all to me, even taking into account @decrep's points above.

From your initial list of the RAC supplied Diagnostic Trouble Codes, there is clearly a major issue with 'lost communications' between the various modules and when the BMS comms is lost, that would surely explain the reason for the HV battery shut down.

Without timestamps and more data then surely only a systematic swapping out of different modules and checking on the wiring between them could fix the issue. from what I remember from the other thread I linked to, the customer's car had to be sent back to MG HV battery centre in the midlands and it took months to be fixed.

As your vehicle was new in February and has experienced faults on 3 out of every 4 journeys, I'd suggest that your reject the vehicle under the CRA 2015. AFAIAA whilst you have exceeded the 30 days short-term right to reject you are within the 6 month right to repair or reject. I believe in your situation, you have to give the dealer one attempt to fix the fault before being able to reject the vehicle - so if the repair has not fixed the fault, you can reject the vehicle. But no doubt others on here will have more knowledge / experience about that process.

I certainly wouldn't be happy continuing to use a vehicle that has failed in such a significant manner on multiple occasions.
 
Doesn't make sense there were no error codes at all to me, even taking into account @decrep's points above.

From your initial list of the RAC supplied Diagnostic Trouble Codes, there is clearly a major issue with 'lost communications' between the various modules and when the BMS comms is lost, that would surely explain the reason for the HV battery shut down.

Without timestamps and more data then surely only a systematic swapping out of different modules and checking on the wiring between them could fix the issue. from what I remember from the other thread I linked to, the customer's car had to be sent back to MG HV battery centre in the midlands and it took months to be fixed.

As your vehicle was new in February and has experienced faults on 3 out of every 4 journeys, I'd suggest that your reject the vehicle under the CRA 2015. AFAIAA whilst you have exceeded the 30 days short-term right to reject you are within the 6 month right to repair or reject. I believe in your situation, you have to give the dealer one attempt to fix the fault before being able to reject the vehicle - so if the repair has not fixed the fault, you can reject the vehicle. But no doubt others on here will have more knowledge / experience about that process.

I certainly wouldn't be happy continuing to use a vehicle that has failed in such a significant manner on multiple occasions.
Thank you. I'll have to google for the CRA2015 rights and procedures. No doubt the dealer will argue strongly against this - where do I take this to after that ? Someone mentioned an ombudsman.

I'll research, but pointers and shortcuts would be very welcome.
 
 
That is incredibly useful thank you.

I've emailed the dealer I bought the car from (MG Barnsley) saying this is the route I'm taking. They are gathering information from MG Wakefield and will get back to me.
 
Well that will put some pressure on them. Not a nice position to be in, but fingers crossed for you. I suspect they will come up with all sorts of reasons to avoid a rejection. Just keep a detailed and accurate log of what has happened as evidence it is not fit for purpose.

FYI if you haven't already found them I think these threads are worth a read.... (both ZS related) - first one is a long read, but very informative, I think.

This second one looks like he got the car fixed, after 3 months without it.
 
If the dealership gets awkward, Moneysavingexpert.com has some useful complaint letter templates which tend to get results.
 
Dealer has responded. To cut to the chase "we don't have any error codes so we can't do anything". They also tried denying my ability to reject after 30 days.

My response FYI...

I accept that I am now outside the initial 30 days.

I have the right to reject the car within 6 months if the dealer is unable to fix a significant fault. The car has suffered two catastrophic failures. You have been unable to fix these faults. I understand that this is largely because you have no fault codes to go by (despite my providing the RAC report) but that does not increase my confidence in the car, rather it reduces it greatly. The lack of fault codes is frankly not my problem.

Of course it's reasonable to make a deduction based on the mileage. Approximately 2200 miles at 45p per mile is around £1000. I accept that. Better than having a car I cannot and will not use in my garage.

Under the CRA it is also your responsibility to collect the car.
 
Dealer has responded. To cut to the chase "we don't have any error codes so we can't do anything". They also tried denying my ability to reject after 30 days.

My response FYI...

I accept that I am now outside the initial 30 days.

I have the right to reject the car within 6 months if the dealer is unable to fix a significant fault. The car has suffered two catastrophic failures. You have been unable to fix these faults. I understand that this is largely because you have no fault codes to go by (despite my providing the RAC report) but that does not increase my confidence in the car, rather it reduces it greatly. The lack of fault codes is frankly not my problem.

Of course it's reasonable to make a deduction based on the mileage. Approximately 2200 miles at 45p per mile is around £1000. I accept that. Better than having a car I cannot and will not use in my garage.

Under the CRA it is also your responsibility to collect the car.
Just keep everything in writing, no phone calls. Keep it cool, don't get carried away and sound angry. Remember that others will read your correspondence and you will get brownie points for being reasonable in your request. I don't think you need to even accept £1,000 deduction, not your fault. Fix it (and provide courtesy car), replace it with new car or refund it.
Keep us updated and good luck.
 
Response from the dealer is a firm "there are no faults to fix, we do not accept your rejection".

Turns out Wakefield MG did a software update after all, not to fix a fault but just to bring it up to date. Hmm.

I'm away for a couple of weeks now without the car. I'll think about it while I'm away. If I still want to reject I'll have to look into how to take it further.

I will find out unacceptable that the car has failed catastrophically and has not captured error codes.
 
Response from the dealer is a firm "there are no faults to fix, we do not accept your rejection".

Turns out Wakefield MG did a software update after all, not to fix a fault but just to bring it up to date. Hmm.

I'm away for a couple of weeks now without the car. I'll think about it while I'm away. If I still want to reject I'll have to look into how to take it further.

I will find out unacceptable that the car has failed catastrophically and has not captured error codes.
Before you go away, I would try the car for a couple of hours, just drive up and down to see what happens.
It could be that there was a simple glitch that was sorted out with software update...

Try it and take pictures and videos as soon as something happens, if it happens. Get RAC to email you breakdown report for your records
 
Just because they didn't find a fault doesn't mean there isn't one. You could argue that they aren't competent enough to locate it and should refer it to their headquaters in Longbridge.
 
Before you go away, I would try the car for a couple of hours, just drive up and down to see what happens.
It could be that there was a simple glitch that was sorted out with software update...

Try it and take pictures and videos as soon as something happens, if it happens. Get RAC to email you breakdown report for your records
I drove it yesterday for a couple of hours. It's driving fine. Just like it did last Monday. Until it fails again, just like it did last Tuesday.

It's possible it was the software update as you say. I suspect I'll have to drive it until it fails again. If it does the same again I'm rejecting no question.
 
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