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Worrying Fault With MG

29K views 43 replies 17 participants last post by  DBedford 
#1 ·
Yesterday I went to drive the car and even put it into gear, but it would not budge. I also got messages on the screen that HV battery was disconnected. After numerous tries for over an hour I could not get it driving. I had to call the MG recovery and when the AA guy came out he also could not get it to drive. He was going to put it on a flatbed, but had one last try and it worked. I will obviously contact MG about this problem, but has anyone experienced anything like this?

Is there a motor with a position sensor that moves contacts to the HV battery? Maybe that was not working? Also I had something very strange happen today. My battery said 78 miles and I drove 4 miles to walk the dog. After an hour of walking the dog, the battery than said 54 miles. I know the GOM varies, but that's a hell of a difference.

Can anyone shed any light on my problems?
 
#2 ·
Yes, I had that happen to me on one occasion when at Milton Keynes Coachway Polar Rapid Charge Hub. The charge was terminated and the HV Battery Disconnected came on the screen. I was in the car at the time and there was a big relay clunk!
I resolved it by turning everything off and disconnecting the Rapid Charger, which also appeared to have tripped, and locking the car. I wasn't sure which had caused the disconnection the Car or Charger. I then unlocked and put my foot on the brak and pressed Start. Everything came back to life but as the Rapid had tripped I move the MG to the next free bay and started another Rapid Charge session so as to complete my journey. It has never happened again since. Talk to your dealer and please post what they say, but personally, unless something repeats and you've something for them to diagnose they're unlikely to want to have the car in to them for inspection given the backlog of servicing they must have after 2 months shut down.
 
#3 ·
If your car turns on (orange light) when you press the start button you might be able to engage gear, but car won't move. The Parking brake is still applied and you get the HV disconnected message on screen. You need to press the brake pedal pretty hard in this situation to get the car too turn on, remembering to put it back into Park first because no EVs will start in drive/reverse.

If your 12v battery is low you might get this message also. Look at the start button, see if you can get car into on mode, press the button once to get the orange LED lit and then again to get it to light the green LED. Then the DC-DC should kick in, if you've got a lighter socket volt gauge you can check this, and you should see the 12v gauge on the dash go to one blob over 12v (at least). Give it a coupe of mins in green ON mode and then turn off and try to start the car as normal (brake pedal/park mode).

Range drop is an interesting thing. For all the comments previously that the MG doesn't have an external temperature thats why it doesn't show outside temp (now being updated). The car clearly did know outside temp. If you parked up with 1 range showing and then the outside temp went up you would see your range increase, and vise versa as you've seen. Most EVs just show the range as you parked and then this can drop suddenly when you get underway (if the temp has dropped). The MG is pretty decent at guessing your range based on changeable weather.
 
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#4 ·
If your car turns on (orange light) when you press the start button you might be able to engage gear, but car won't move. The Parking brake is still applied and you get the HV disconnected message on screen. You need to press the brake pedal pretty hard in this situation to get the car too turn on, remembering to put it back into Park first because no EVs will start in drive/reverse.
But the strange thing is the car was not on the orange, the green was clearly on the start button.
 
#7 ·
I did have an odd problem on Friday at a Polar. I charged normally, but during charging I was checking the 12V battery with clock/thermometer/voltage thing I got off AliExpress, and I turned the car on and off and locked and unlocked it a few times. I think this confused it!

Charging finished normally after the short top-up. When I disconnected I then got the message HV disconnected and the car would not move! I tried putting it in drive and back to park a few times. I think I had to turn it off and back on twice, with foot hard on the brake and then it was back to normal and I drove home without further problems.
 
#8 ·
When I disconnected I then got the message HV disconnected and the car would not move!
Paul, I had the same experience after charging at Milton Keynes Polar Rapid when the charging terminated prematurely and displaying the same message. Annoying because I needed to move to another stall to complete the charge as the Polar Rapid wouldn't come back online. I think it was the Polar confusing the car's onboard system. Getting out and locking the car then starting all over allowed me to move the car and in a fresh stall, all was good.
 
#11 ·
Yes I have had that on 2-3 occasions but in each case getting everyone out of the car locking it and then waiting a minute and starting over again it was fine. First time it happened I faffed around for 20 minutes while in the car but until I actually got out and locked the car without anyone inside I would still have HV Battery Disconnected fault on the screen. Dealer found nothing wrong. The second time I knew what to do. The third time I was on my drive and I jumped out locked it and then unlocked it straight away and it was fine after that.
 
#14 ·
Yes I have had that on 2-3 occasions but in each case getting everyone out of the car locking it and then waiting a minute and starting over again it was fine
It's when you turn the drive button before the system is ready to move off. Just press the start/stop button to turn the car off, wait a couple of seconds and turn back on again. Take a deep breath (well just wait a couple of seconds) until you are sure the system has settled down and try to put it into drive again. I've done it quite a few times, I'm used to getting into the Zoe pressing the start button and putting it into drive. No problem. The MG is a tiny bit more touchy and likes to take it's time.

it's a :sleep:head

I now turn the car on and put my seatbelt on. I find this is long enough for the bing to sound and the system to be ready.
 
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#15 ·
It's when you turn the drive button before the system is ready to move off. Just press the start/stop button to turn the car off, wait a couple of seconds and turn back on again. Take a deep breath (well just wait a couple of seconds) until you are sure the system has settled down and try to put it into drive again. I've done it quite a few times, I'm used to getting into the Zoe pressing the start button and putting it into drive. No problem. The MG is a tiny bit more touchy and likes to take it's time.
That was not my experience, as even the AA man could not get it to work. It seemed to go into a permanent lockup.
 
#17 ·
Just a clarification to my last post "it's not been what I have done when I have had this problem so there are probably multiple causes. " There have been occasions when I first had the car that I selected R too soon and the car refused to drive but I soon found that out on this forum which is why I know that I have also experience when I've not rushed the start-up and I've had to get out and lock the car to reset.
 
#22 ·
I have not had this experience on my car ( yet ).
But, I have seen something fairly similar in my previous VW PHEV on two occasions.
I was waiting outside of my daughters house to give her a lift one day.
The car was totally powered down, but just the radio playing.
As she entered the car I placed my foot on the brake ( lightly ) and hit the "start" button, I was a little to quick to pull back on the DSG lever before I got the "ready" light.
Oh ..... the car DID not like that at all !.
It refused to move one way or the other.
Then it put up a "hybrid failure warning" on the dash.
I tried all sorts in an attempt to get the car moving, absolutely nothing !.
Then I powered down the car, we all got out and I relocked the doors.
After a few minutes, I unlocked the car and when through the start up process at a more slower pace.
The car booted fine and we drove away.
It did the very same thing about 12 months after when I was in a real rush to move the car and it did the very same thing.
I came to the conclusion that the car has a certain start up protocol that is brilliant, as long as you don't try and skip the steps.
If you interrupt it's little wake up call, it is likely to crash the system because you are demanding functions before it has got it's full act together correctly.
It is unsure of what is being demanded, so it falls on it's arse and locks up.
We are driving computers on wheels affectively today.
They do a great job, but they like to operate at a speed that THEY want too and not a speed that we expect sometimes !.
Don't rush the system out of bed to early, or it may react like a bad teenager ;) .
 
#23 ·
I get my Comfort 2 update when the MG is in for 1st annual service at the end of the month, lockdown permitting. I scheduled it for the same day in the hope of more acceptable fee and I've been quoted a much more reasonable charge that when it first came out as a stand-alone job. The Comfort 2 seems to boot up quicker with all the fancy stuff but I've not timed and compared how long it takes to go from Press to Ready when I've driven service loan cars recently but it seems a lot less fussy in all other respects.
 
#24 ·
It's not perfect, but it does make for a much more pleasant experience.
 
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#25 ·
Possibly it is as a result of putting in drive too quick, but on FB the reply to this message is your foot is not pressing hard enough on the brake pedal or for long enough.
It was mentioned above it may show an adult is in control if brake pedal is pressed hard and maybe why a dealer replaced a brake pedal switch thinking it was faulty.
 
#26 ·
Same problem today after rapid charging of MG5 ev. Tried to switch power on and put into drive,following happened - warnings of yellow battery with line thru, red battery and written warning “HV battery shut off” and car dead. Manual points to LV BATTERY disconnection. Spoke to dealer who recommended call AA and retrieve the car. Read advice in this thread and followed. Let car sit and all dashboard lights go off - locked car and walked away from key range. Then went slowly through pressing once for ready, waiting then pressing in usual way to restart ( brake pedal and press start). Happy car again and happy driver. Feel like I’ve had advice from the IT crowd - have you tried turning it off and on again!
 
#27 ·
Please post this on the 5 group page too, need to keep track of faulty (or otherwise) in the correct areas. (y) You'll probably find some 5 owners don't frequent the ZS area because they are so offended with the ZS for whatever misplaced reason. :ROFLMAO:
 
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#31 ·
I had exactly the same thing happen to me at an Instavolt charger two days ago. It got to 95% and stopped. I got the same message as you and I could do nothing. I called out the AA, who was there in 15 minutes. When he got there, I tried again and all was well. The AA man said that actually leaving the car and walking away with the keys was probably what cured it. He said that while the keys were in the vicinity of the car, they kept talking to each other, and therefore the car was not completly shut down. He said that the fault was probably the computer in the car sensing a possible fault and protecting itself. So if it happpens to me in the future, that's what I'm going to do. Lock the car and walk away for 5 minutes. Some people advocate taking off the negative terminal from the 12 volt battery and re-attaching it after a minute, but letting the car completely shut down and re-boot seems to have done the trick for me.
 
#32 ·
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#33 ·
Hi all, I found this thread after I had this happen this morning to me. However, I have the MG HS executive 21 model. Not the elec. I turned the car on as normal, put it into reverse and it wouldn't move. Tried in first gear, same thing. After about 5 minutes, turning the car on and off it eventually drove.

Also had issues where the reverse camera wouldn't load up on the screen and the music wouldn't play. Has anyone had a response to what caused the initial problem?
 
#34 ·
HI Tommy, I'm wondering if you ever resolved the issue you described. I live in New Zealand and was told something along the lines of hydraulic pressure being trapped in the brakes. Apparently when this happens you have to: turn the car off, push VERY hard on the brake until the pressure is fully released, then it should start. My EV is in the shop right now to ensure nothing more serious happens - fingers crossed. It was extremely disconcerting and seems like either 1) a fault or 2) something new owners should be clearly told about. I still feel quite unsettled with the car, so would love to hear if it's happened again to you. This is now my 3rd time, but I was told I'm not the only one this has happened to.
 
#36 ·
Today I experienced something I could not find any answers from neither the dealer nor the service, and I would like to know if anyone else has experienced the same or similar issue. I just got the MG ZS EV two days ago and it was a new car. I haven't recharged it yet since I got the car. However yesterday I spotted some peeling on the gear selection wheel so I brought back the car to the dealer with service. While they were inspecting it the service manager decided to pull the car a little bit more front but when he started the car and get the gear to "D" the car did not move, the car started to go down from the ramp. Then he immediately called the dealer, he came and hit the gas pedal the car started to go backwards instead of going forward the car. They tried to turn it off and on but did not change the situation. The service manager says there were no messages or warnings on the screen. Then we towed the car from where it parked after that we tried it again then it worked without a problem. But I feel bad about the situation here, I think it was a great chance that happened at the service and both the dealer and the service manager has witnessed that but I am worried about if this ever happens again and what if there would be a person or an animal behind the car and I may harm them. I probably can not even prove that I put the car on "D" but it went reverse in that case. What are your suggestions please share.
 
#37 ·
Put the seatbelt on. ZS won't move unless your plugged in to the seatbelt. Its not driving backwards, its rolling.
 
#41 ·
Hi Everyone, I've had my ZS EV for almost a year now. I seemed to randomly get the amber HV warning light and then had to switch the car off and restart. Recently I got a red HV warning saying start the car immediately, but it wouldn't start! Long story short, I found a thread which also mentioned that if you don't press the brake pedal hard enough or for long enough on start up, it doesn't like it! Now I press the brake until it's completed its scan and I've heard the bong of the ready light coming on. Hasn't happened since so I'm hoping that's the reason as I absolutely love the car. Mk1 2020.
 
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