Control error, HV battery disconnected

[Rich44]

So today I was driving along a week after cars first service, typical, and the above error happened. Car died, steering died, brake assistance died. All 12v systems stayed running over & car rolled to a very quick stop. Luckily happened in a quiet village at 20mph not motorway.

Pulled 12v battery to reset car & drove off OK. Got home & was able to replicate problem again by turning aircon on.

Now HV battery is completely dead & won't recover.

Anyone come across this before?

RAC took 3 hours to come out & by that time dealer was shut so they have to come back tomorrow & try again.

I'm wondering if the aircon compressor went faulty & blew a fuse somewhere out of the way because it was fine until I put the aircon on. Any thoughts welcome. Thanks

 

[Coulomb]

I'm wondering if the aircon compressor went faulty & blew a fuse somewhere out of the way because it was fine until I put the aircon on.

Yes, that's possible. If it did blow a fuse, it will be in the high voltage circuit, so not user accessible for obvious reasons But that should not disable the vehicle.

The other possibility is that moisture has gotten where it should not, and caused an electrical leakage. Two or three such leakages and the vehicle system will probably have had enough and made it a permanent fault code, disabling the HV contactors.

Now HV battery is completely dead & won't recover.

Well, the HV battery will be fine, just not accessible.

 

[Rich44]

No fault codes stored, it's been checked. Obviously regarding the battery by not recover I meant that pulling the 12v battery fixed it earlier but doing so now does nothing I know the HV battery itself is fine. If I hook it up to charge I get connected but not charging which fits with it too. Got a bad feeling this is gonna be a looooong fix no slur on MG just seems to be one bad thing after another last few years or so.

Typical that motability can't seem to get a hire car either while point in using them ***

Thanks

 

[Coulomb]

I know the HV battery itself is fine.

I thought that would be the case, but I didn't want other readers panicking that their HV battery might drop dead any minute and cost a fortune to replace.

 

[Lovemyev]

So today I was driving along a week after cars first service, typical, and the above error happened. Car died, steering died, brake assistance died. All 12v systems stayed running over & car rolled to a very quick stop. Luckily happened in a quiet village at 20mph not motorway.

Pulled 12v battery to reset car & drove off OK. Got home & was able to replicate problem again by turning aircon on.

Now HV battery is completely dead & won't recover.

Anyone come across this before?

RAC took 3 hours to come out & by that time dealer was shut so they have to come back tomorrow & try again.

I'm wondering if the aircon compressor went faulty & blew a fuse somewhere out of the way because it was fine until I put the aircon on. Any thoughts welcome. Thanks

Sorry, but which model MG are we talking about here folks ?.
“The car has just been in for its first service last week”.
MG 5 / MG ZS EV Gen1 I suspect ???.
One year old I presume, how many miles has the car covered, does it take a lot of smaller trips ??.
Could it be a 12 Volt battery issue ?.
If the 12 volt status is low due to taking a lot of short trip, it could dropped to a SOC that will close down the car ???.
It has to be the first thing to check surely ??.
The HVAC is powered by both the 12 volt battery for the blower motor and the HV battery for the A/C and the cabin heater.
What was the 12 volt battery status gauge displaying, can you remember.
EV’s are more reliant on a good SOH on the 12 volt battery, more than most people think.
Hope it is a quick fix !.