MG5 System Fault Help Please

P

PonteMG5

Established Member
Joined
Oct 23, 2021
Messages
76
Reaction score
80
Points
27
Location
West Yorkshire
Driving
MG5
Well what a way to spend Xmas day evening. Waiting probably another hour for MG assistance but came to top up battery today at Elland Road Park and ride and charger wouldn’t work. On to next I thought only to find car had system fault warning when trying to turn on followed by HV battery shut down.

Hoping AA as MG assistance will be able to get me moving again? I have got my wife alongside me in her ZS and we do have a 10mm spanner but the cover on the bonnet has plastic screws and don’t have anything to get them open. Thought I heard you could disconnect the battery and it normally solves these issues. Never had this before but typical it happens on Xmas day. Just sat waiting now….
 
Something about failed charges upsets the 5, disconnecting the battery can help, just turning the car off and leaving it for 20 minutes can do the same thing. If neither of these works then the AA guy will plug his diagnostic gizmo in and 'clear' a non existent fault which will do the trick.
This happened to me a few months back and the AA tech said there was a firmware upgrade that supposedly fixes the issue.
 
Thanks just a waiting game told now it will be between 8-9pm but will be a dedicated AA patrol, they did try to subcontract to a recovery service which would be approx 730pm but didn’t feel too confident about that.
Left car for a while and hasn’t sorted itself and with what I have on me can’t disconnect battery so reassuring to know that AA may be able to get me moving. Have about 26miles range to get home 15mins on motorway so hopefully can crawl it home and charge overnight. Don’t won’t to risk another charger messing me up again tonight
 
Basically yes.
Using the torch on your phone, disconnect the negative (- ve) terminal. Make sure it's tucked well away from the positive (+ ve, usually red) cable that remains attached to the battery and it's not touching any other metal part of the car. No need to disconnect both because disconnecting the negative will break the 12 volt circuit.
Good luck, keep us posted.
 
Subcontracted service from AA finally turns up at 945pm, great lad to be fair. Tried his diagnostic machine but couldn’t connect and he did say theirs weren’t as good as AAs so then tried the disconnect of battery and this also didn’t work. So had to leave it and write the day off and will try getting AA to turn up proper in the morning. Can’t say I’m that enamoured with them but do appreciate it’s Christmas but has a few porkies from them
Today
 
This issue happened exactly same way recently; issue with charger not charging then hv battery shut off; waited almost 3 hours till 10 pm; eventually local garage couldnt reset the hv ( after ensuring 12v battery ok) he gave me a loft home (30 miles) i returned the next morning by train as i thought would need towed to garage but aa guy wanted to reset instead; got it working & been ok since.

Can i ask what the hardware update is???
As i would be much happier never having this issue with charger anxiety again!
 
Well here this morning and finally the AA are here, but need another AA van as his 14 volt charger wasn’t working. Why you ask? Well the diagnostics machine couldn’t talk to the car and the usually rock solid 12v battery was sitting nearer 11 so thinking it could be this needing a boost. So second van now here to hopefully resolve, only other option is a tow.
 
So alas didn’t work and second diagnostic machine couldn’t talk with car so now been towed home and will be in touch with garage tomorrow to have it taken there for them to sort out. What an ordeal but at least can now enjoy day knowing car is at least safe. Thinking it might need a complete reset or something as now it cycles through lots of faults on startup like high beam not available, auto hold not available etc. AA man says they get lots of call-outs where the chargers are messing up vehicles software.
 
PonteMG5 said:
So alas didn’t work and second diagnostic machine couldn’t talk with car so now been towed home and will be in touch with garage tomorrow to have it taken there for them to sort out. What an ordeal but at least can now enjoy day knowing car is at least safe. Thinking it might need a complete reset or something as now it cycles through lots of faults on startup like high beam not available, auto hold not available etc. AA man says they get lots of call-outs where the chargers are messing up vehicles software.
Click to expand...

The cycled errors is normal when you've had the 12v battery off, they clear up after 5 minutes of driving. Everyone suggests the 12v battery trick to clear issues, but forget to warn the person that they will see every warning message under the sun whilst the system re-learns what it's got attached.

My cars been flawless for last 9 months, but I've only used 1 rapid charger in that time and this kind of issue would be my main concern when planning a longer trip, not charger availability, but finding ones that are function and wont turn the car into a paperweight.
 
The plot thickens, car now dropped off and still a very nice looking paperweight. Parked off drive onto road so too far away from my charger which wife’s car will need to access anyway. So thought I would try the granny charger and it says charging on the unit but the car won’t actually charge?! All of this after simply plugging into a rapid charger that wouldn’t work.

Let dealer handle it tomorrow so call into Luscombe first thing.
 
PonteMG5 said:
So thought I would try the granny charger and it says charging on the unit but the car won’t actually charge?!
Click to expand...

Interesting that the car has got through the handshake routine with the Granny charger but apparently is unable to set the contactors for the HV battery.
 
I've had this happen twice...
First time at Fleet Services Soutbound: tried disconnecting the 12v batter with no result. AA cleared the fault log and all was good after that.

Second time at Cobham Extra (M25). After a lot of faffing around I turned of everything and walked away for 10 minutes. After that all worked normally...
 
atrayf said:
I've had this happen twice...
First time at Fleet Services Soutbound: tried disconnecting the 12v batter with no result. AA cleared the fault log and all was good after that.

Second time at Cobham Extra (M25). After a lot of faffing around I turned of everything and walked away for 10 minutes. After that all worked normally...
Click to expand...
AA couldn’t get the machine to even talk to the car so couldn’t clear it, basically have a car which seems to be totally corrupted by a dodgy charger.
 
I doubt that the charger has corrupted your car's firmware, they just don't have that level of access. More likely it's the firmware getting itself in a tizz because things didn't go the way it expected them to, didn't get some stop or release message that it expected and think's there's a fault as a result.

Up until your AA guy couldn't connect, your issue was identical to the one I had before. When my AA guy connected his pad to the obd2 it showed no errors. AA guy said this is normal but if they do a fault clear anyway it fixes the problem with the car.
I think it'll be a pretty easy fix when the dealer get's it into the workshop, mention to them about the firmware update, just in case they hadn't heard.
 
5teep said:
I doubt that the charger has corrupted your car's firmware, they just don't have that level of access. More likely it's the firmware getting itself in a tizz because things didn't go the way it expected them to, didn't get some stop or release message that it expected and think's there's a fault as a result.

Up until your AA guy couldn't connect, your issue was identical to the one I had before. When my AA guy connected his pad to the obd2 it showed no errors. AA guy said this is normal but if they do a fault clear anyway it fixes the problem with the car.
I think it'll be a pretty easy fix when the dealer get's it into the workshop, mention to them about the firmware update, just in case they hadn't heard.
Click to expand...
Yeah don’t think the charger has necessarily corrupted the car on its own but it’s def the causal factor in the car developing the issue. I’m not concerned really in it getting fixed as under warranty, but it does raise a question of this is so easily caused as could easily have had kids or being in a more isolated spot.
 
I had a gridserve charger cause this on my 5, turning the car off and leaving it for a few minutes seemed to clear it (I'm not sure how many minutes it was as I ended up popping into the services to use the facilities)

Edit: I think mines getting a BMS update as part of trying to solve the "Check HV battery" errors, it will be interesting to see if it's more reliable on rapid chargers after that.
 
This charger was a “charge car” which I believe is now BP Pulse. It’s been left now over 24hrs and the fault remains so it does feel like the car has shut down. Spoken with garage this morning and will hopefully be collected tomorrow and will update as to what it ended up being.
 
I just tried my first rapid charge on my MG5 Facelift trophy LR and got a HV battery failure.
Was at an EV Power charger.
Steps to charge
Touch Electric Universe Octopus card again charger.
Followed instructions.
Connected cable.
Press start.
Connection failed.
Car beeped with red battery light coming on.
On charger pressed try again and it worked.
Charged to 80% (very quick).
Then stopped charge on charger.
Got in car no errors.
Tried to put car in drive and got HV error with beeps.
Having read forum I did not immediately panic.
Went for easy option first and turned car off and back on.
Error gone car all good.

This was my first rapid charge so hoping that was my worst experience and all clear along ahead.
I picked up the car 4 days ago and all updates were installed before pick up.

Going to try another different make one tomorrow see what happens.

Side note the charger centre was amazing. Very clean nice roof over it.
5095D9BA-803F-4EAD-BAC8-2DDD36253282.jpeg
 
Support us by becoming a Premium Member

Latest MG EVs video

MG3 Hybrid+ & Cyberster Configurator News + hot topics from the MG EVs forums
Published
Subscribe to our YouTube channel
Back
Top Bottom