Breakdown

[PeteJ]

I had stopped for a short time but when i tried to restart the message ' control unit faulty' or something similar, this was followed by ' High voltage disconnected'. After waiting and then retrying the car still would not start despite going through all of the normal start up process. I phoned MG assistance but after waiting for 15 minutes tried restarting and this time she came fully to life. My dealer Richmond of Southampton can not provide me with a courtesy car before Dec 8th. Have any of you had the problem, if so did it reoccur or do you know the source of the problem as i would hate to be stuck some ware waiting for MG assist to respond.

 

[Mgkev]

Hi Pete, sorry to hear of your issue. My view is that it might have been a one off. My father had a similar issue with his Renault Megan. His car just stopped and refused to restart. The AA guy could not find anything wrong and it never happened again.
I’d say wait and see what occurs in the near future. I wouldn’t expect Richmonds to find the fault anyway.

 

[Tango130]

I had stopped for a short time

Whilst you were stopped I guessing the car wasn't in 'Ready' mode? The 12v battery would have been discharging, which could have caused your issue.

 

[PeteJ]

I had just finished a 12 mile trip and the car had only been in ready mode for about 2 min.

 

[Roar JAcobsen]

Hi PeteJ
I have had the same error messages ("Vehicle control system fault" and "HV battery shut off") 3 times when starting from home. Two time it started after multiple start, power off and start again for approximately 20 minutes. The second time it happend I needed roadside assistance to transport the car 150 km to the garage. And of course, now the car starts. They can not find anything wrong, but does a SW update. I get my car back, and after a week it happens again. Hopefully I will get a solution. But for now, all I know is that the case has been submitted to the technical department

 

[Jake]

In my early days of ZS ownership I had one or two 'odd' things happening on start up including the HV disconnected. Reading other owners similar experiences the consensus of opinion seemed to point towards keeping the brake pedal depressed long enough during start procedure. I now always keep my foot on the brake pedal and follow the pedal down towards the floor until the dash display becomes Ready. I find it strange how the brake pedal resistance is solid initially but gradually goes softer as the car readies itself and then pressurises when Ready shows up? However I haven't had a problem on start up since adopting this procedure and it has become second nature to do this. Hopefully if it is a real fault MG have sorted it by now and you are back on the road. Good luck if they haven't.

 

[Roar JAcobsen]

In my early days of ZS ownership I had one or two 'odd' things happening on start up including the HV disconnected. Reading other owners similar experiences the consensus of opinion seemed to point towards keeping the brake pedal depressed long enough during start procedure. I now always keep my foot on the brake pedal and follow the pedal down towards the floor until the dash display becomes Ready. I find it strange how the brake pedal resistance is solid initially but gradually goes softer as the car readies itself and then pressurises when Ready shows up? However I haven't had a problem on start up since adopting this procedure and it has become second nature to do this. Hopefully if it is a real fault MG have sorted it by now and you are back on the road. Good luck if they haven't.

I was also told by a mechanic to press very hard hard and long on the break pedal, but that did not work for me. I have just read a comment posted by Mark Holmes which refer to low voltage on 12V battery and thereby can cause different fault symptoms.

 

[Kithmo]

I was also told by a mechanic to press very hard hard and long on the break pedal, but that did not work for me. I have just read a comment posted by Mark Holmes which refer to low voltage on 12V battery and thereby can cause different fault symptoms.

No need to press hard, just maintain pressure like @Jake said.
My foot goes on the brake when I'm ready to start the car and stays there until I'm ready to move in D.

 

[Ingo Wilson]

I had stopped for a short time but when i tried to restart the message ' control unit faulty' or something similar, this was followed by ' High voltage disconnected'. After waiting and then retrying the car still would not start despite going through all of the normal start up process. I phoned MG assistance but after waiting for 15 minutes tried restarting and this time she came fully to life. My dealer Richmond of Southampton can not provide me with a courtesy car before Dec 8th. Have any of you had the problem, if so did it reoccur or do you know the source of the problem as i would hate to be stuck some ware waiting for MG assist to respond.

I had the same problem at a motorway services +200 miles. Richmond, Southampton could give me no support or advice! AA came out after two hours and although clueless about MG ZS EV's got me going after connecting his laptop and resetting 'things'. Other semi technical issues which my MG dealer couldn't support/advise me on this Forum could.

 

[Cocijo]

No need to press hard, just maintain pressure like @Jake said.
My foot goes on the brake when I'm ready to start the car and stays there until I'm ready to move in D.

I think that all you’re doing when you depress the brake pedal to start is connecting a circuit switch attached to the brake pedal. The movement of the pedal is the servo assistance system powering up.

 

[Cocijo]

I had stopped for a short time but when i tried to restart the message ' control unit faulty' or something similar, this was followed by ' High voltage disconnected'. After waiting and then retrying the car still would not start despite going through all of the normal start up process. I phoned MG assistance but after waiting for 15 minutes tried restarting and this time she came fully to life. My dealer Richmond of Southampton can not provide me with a courtesy car before Dec 8th. Have any of you had the problem, if so did it reoccur or do you know the source of the problem as i would hate to be stuck some ware waiting for MG assist to respond.

I’ve had similar issues early on. I think that it may have been mostly down to me not using the car correctly. Your issue may be something completely different. The 12v battery drains very quickly and it’s important that when parked and leaving items on - e.g. heater that you have the high voltage system engaged. I’ve even managed to select drive and reverse without the HV system engaged and although it shows on the selector and the dash there’s no drive.

 

[Mgkev]

@Ingo Wilson , now you know not to bother Richmonds with technical questions.
MG UK are massively behind with their training courses and this is not likely to get resolved any time soon.
In short a great car let down by a poor dealership network. SAIC should have set up their own network like Tesla have .

 

[Cocijo]

@Ingo Wilson , now you know not to bother Richmonds with technical questions.
MG UK are massively behind with their training courses and this is not likely to get resolved any time soon.
In short a great car let down by a poor dealership network. SAIC should have set up their own network like Tesla have .

Hmmmm Tesla aren’t that great I’m afraid To say.

 

[Kithmo]

I think that all you’re doing when you depress the brake pedal to start is connecting a circuit switch attached to the brake pedal. The movement of the pedal is the servo assistance system powering up.

Brake light switch probably, that's what the Prius uses.