Vehicle Control System Fault

[Geoff Campbell]

Our faithful and mostly trustworthy 2020 ZS EV has just thrown a Control System error. Fortunately we're at home, and don't need to be anywhere any time soon, but I thought I would throw it open to the panel, see if there's anything else to try:

1) I've disconnected the 12v battery earth for 15 minutes, didn't fix it
2) I've connected an OBD2 dongle, and a generic OBD2 program found no faults. Tried sending a clear command anyway, also didn't fix it.
3) The 12v voltage was creeping down towards 12v (err, as it were), so I've now got the 12v battery disconnected and on a smart charger. I'll give it three hours then try reconnecting, you never know...

Have I missed anything? I'm pretty resigned to phoning the dealer tomorrow morning for a warranty repair.

GJC

 

[Lovemyev]

Our faithful and mostly trustworthy 2020 ZS EV has just thrown a Control System error. Fortunately we're at home, and don't need to be anywhere any time soon, but I thought I would throw it open to the panel, see if there's anything else to try:

1) I've disconnected the 12v battery earth for 15 minutes, didn't fix it
2) I've connected an OBD2 dongle, and a generic OBD2 program found no faults. Tried sending a clear command anyway, also didn't fix it.
3) The 12v voltage was creeping down towards 12v (err, as it were), so I've now got the 12v battery disconnected and on a smart charger. I'll give it three hours then try reconnecting, you never know...

Have I missed anything? I'm pretty resigned to phoning the dealer tomorrow morning for a warranty repair.

GJC

Sounds very much like a low SOC on the 12 volt battery TBH.
My smart charger has a battery indicator status indicator on the front, if you connect to a battery with a low SOC it can be seen on the front panel.
At least this gives you a quick insight into the batteries SOC as you place the car on charge.
Of course your battery could have failed, but I would give your current battery a really good overnight charge and then go from there GJC ?.

 

[Geoff Campbell]

Sounds very much like a low SOC on the 12 volt battery TBH.
My smart charger has a battery indicator status indicator on the front, if you connect to a battery with a low SOC it can be seen on the front panel.
At least this gives you a quick insight into the batteries SOC as you place the car on charge.
Of course your battery could have failed, but I would give your current battery a really good overnight charge and then go from there GJC ?.

Well, the voltage on the battery was pretty good - that "heading down to 12v" thing was after an hour of fiddling around with the car. Still, we'll see later, if it doesn't start up this afternoon I'll leave it on charge overnight.

I wonder if it's relevant that the car had a software update when it was in for a service a couple of months ago? Maybe they've tightened up the voltage limits that they work to, or something?

GJC

 

[Lovemyev]

Geoff - Do you know what software update they performed ?.
Pure guess on my part here, BMS update do we think ?.
How many miles have you covered and do you carry out regular / any D/C rapid charging on route, or are you a pure A/C charging person e.g. Wall box / Granny unit.
It is worth the bother of charging the battery overnight, because the dealer will head straight for the 12 volt battery IF it needs to go in to be looked at.
It’s the heart of any car of course, but it has become the easy target on an EV because it has become the “Go To” fault.
Hopefully now the battery has been disconnected for a few hours and it has been fully charged, it will boot normally .

 

[Geoff Campbell]

Geoff - Do you know what software update they performed ?.
Pure guess on my part here, BMS update do we think ?.
How many miles have you covered and do you carry out regular / any D/C rapid charging on route, or are you a pure A/C charging person e.g. Wall box / Granny unit.
It is worth the bother of charging the battery overnight, because the dealer will head straight for the 12 volt battery IF it needs to go in to be looked at.
It’s the heart of any car of course, but it has become the easy target on an EV because it has become the “Go To” fault.
Hopefully now the battery has been disconnected for a few hours and it has been fully charged, it will boot normally .

I don't know what software they loaded, I'm afraid. I find the MG very opaque as an owner, although to be fair that's probably partly because I don't do much with it.

Miles - we've done about 15,000 now, over 3 years. It's our second car, mostly used locally and charged at home on a 7kW AC charge point. However, I did take it to Newcastle and back last week, racking up 800 miles and 8 DC fast charges in three days. It seemed happy enough when I got back, and has done a few local journeys since, but...

It's not booting up properly still, so I'll leave the Optimate connected overnight and see what we get in the morning.

GJC

 

[TrickyPowell]

Sounds very much like a low SOC on the 12 volt battery TBH.
My smart charger has a battery indicator status indicator on the front, if you connect to a battery with a low SOC it can be seen on the front panel.
At least this gives you a quick insight into the batteries SOC as you place the car on charge.
Of course your battery could have failed, but I would give your current battery a really good overnight charge and then go from there GJC ?.

I have similar issues and the dealer cannot fix. Did you get yours sorted? Mine has just done it for the third time and I am in France on holiday.