MG5 Mystery Faults

[Squidder]

Hello all!

Just an interesting story for you all. This is the story of my '72 plate MG5LR Excite and it's mystery magically disappearing faults that have now led to it being kept in for investigation by the dealership.

I took delivery about 3 weeks ago now and have nothing but good things to say about this car. That may sound strange considering the title of this post but that is why they are a mystery!

Numerous times the car has popped up this message at various speeds and various states of charge... At no point has the messaged affected the driving, power delivery or use of the vehicle

And then it dissapeared within 20 to 40 seconds!

The car has had long balance charges overnight on my driveway on the Granny charger and at work on a 7kw charger. Only supercharged a couple of times.

Combine this with the mystery of auto-hold handbrake disabling itself when the car has been parked on a somewhat inconsistently random basis, the radio sometimes swapping to AM and 2/3rds volume in a similar fashion I dropped it off with local dealership who announced today that after speaking to MG it's a new unseen before combination of errors!

Has anyone else had anything like this? My googling said no before I took it in and couldn't even find any reference to "check HV battery" when speaking to MG support last week.

Interesting..... The worst part of the whole escapade is I was given a PETROL courtesy car. Sad times indeed

 

[5teep]

Intermittently bad connection coming from the HV battery, or the same issue on a sensor??

 

[smokie]

Ask them to check/swap the 12v battery. Often seems to be at the bottom of spurious faults. (I know it's new but...)

 

[Tweed98]

Combine this with the mystery of auto-hold handbrake disabling itself when the car has been parked on a somewhat inconsistently random basis,

I assumed that was a "feature" when it happened to mine. Others in my company car support group have mentioned the auto braking needing to be switched on every journey.

 

[Silver estate]

I assumed that was a "feature" when it happened to mine. Others in my company car support group have mentioned the auto braking needing to be switched on every journey.

If it didn’t need switching on every journey why would there be a separate button
or is it to hard to press a single button it is beside the PARK BRAKE switch , which would be used when parked up for any length of time , auto hold is a type of hill assist and would only be used in traffic not when the car is parked unattended

 

[Tweed98]

If it didn’t need switching on every journey why would there be a separate button
or is it to hard to press a single button it is beside the PARK BRAKE switch , which would be used when parked up for any length of time , auto hold is a type of hill assist and would only be used in traffic not when the car is parked unattended

If a system has the name "Auto" why does it need to be turned on every time?

I am familiar with these systems VAG cars have the same switch layout for about 7 years and the system remembers your settings. I have the same switches and systems in the Seat Leon that I have had for the best part of 5 years.

Can anyone mention any problems or mention anything less than perfect without the MG Ultras jumping down their throats?

 

[smokie]

I suppose the point is that not everything which is discussed as a problem is not seen a problem by everyone.

In this case it seems the problem is just that it works differently to what you're used to really.

 

[Tweed98]

Different manufacturers do things differently. I quite like the car, it gets down the road really well and is comfortable but some of the software choices are sub-optimal!

 

[Squidder]

I assumed that was a "feature" when it happened to mine. Others in my company car support group have mentioned the auto braking needing to be switched on every journey.

I would understand if I had to do it every time, it is the inconsistency that made me think it was a bug! Oh well

 

[Squidder]

But general update!

I have the car back and the official response from the dealership and MG IS............

They have no idea. The car has been checked over fully over the 2 days, checked that it is up to date on all software (it was) and to wait and see if it comes back.

My current theory is that as it's October my car is channelling "Christine" vibes....... But we shall see and if anyone wants updates I'll keep dropping them in here.

Ask them to check/swap the 12v battery

That was investigated by myself beforehand having read this forum and was all happy voltage wise, garage confirmed they had checked it also.

Ever onwards and I'm dropping a friend down to Bristol tomorrow so see if it pops back up!

 

[Squidder]

Well. A story of the mystery Faults you want? Well today our tale got more interesting.

Granny charged up to 85% Fri night, did runarounds Saturday, granny charged all the way to 96% overnight for the run to Bristol airport, 140 mile round trip, no issues. Commute Monday fine, left home this morning with ~65% charge and here we gooooo.

0852 - Check HV Battery. 62% -Cleared within a minute
0906 - Check HV Battery. 57% - Just as I'm on the dual carriageway section of the a40 heading west into Cheltenham. Get down the hill and just in towards Charlton kings
0907 - Power Limited. limiting Speed. 57% battery - thank god this didn't happen a mile or 2 back I'd have been in a helluva place. 20mph max i crawl onto the side of the road, shutdown car, get out, lock, Bluetooth off and leave it for 4 minutes .

Get back in, fault still there, accept I'm going to have to crawl it to a side street/quieter bit of road as I'm currently bumped on the curb.

Start driving, go through a set of traffic lights, reapply power and shoot forward! Look down the fault has gone!!! Decide I'm going to try and get as far as my office

0918 - Check HV battery is back! But still got power

MG dealership in Gloucester took all day to ring me back with a "plan of action" which seems to be "no idea, bring it in next week". MG say it's the dealers responsibility to sort and I'm pretty darn peeved (other non forum suitable words are available).

I've driven home this evening with no issues but in the mean time I've got a car that's russian roulette as to whether it'll do 60 or 20, no one having a clue why, no one taking real responsibility and not a chance of me putting my family in the vehicle!

Excuse the rant, but I'm keeping this documented online so if this ever happens to anyone else, they know it's not just them!

 

[5teep]

I'd write to the dealer rejecting the car, you can do this up to 30 days after purchase. At worst you get a different car but maybe it will spur them to get it fixed for you.

/edit it has to have gone faulty within 30 days, you don't have to reject it within 30 days, sorry.

Know Your Rights: How To Reject A Faulty New Car

Buying a new car is an exciting experience, however sometimes things can go wrong. If you're choosing to reject your vehicle, do you know your rights when it comes to do so? We've got everything you need to know in this comprehensive guide.

www.motoreasy.com

 

[smokie]

I'd write to the dealer rejecting the car, you can do this up to 30 days after purchase.

Absolutely this. Nothing to lose really, don't hesitate.

 

[EVsince2016]

If I was you I'd pop into Cleverley Autos, they are the experts and lucky for you based in Cheltenham!

 

[SDP79]

Combine this with the mystery of auto-hold handbrake disabling itself when the car has been parked on a somewhat inconsistently random basis,

You are having a terrible experience and have my sympathy. The only solution seems to be as you say reject car - good luck and please let us know how you get on.
Regarding the auto parking brake, I have the same issue. The auto hold should reset after every journey not matter how short the time between journeys - but it does not. It acts randomly. Sometimes when you pop to shops and leave car for few mins it does not reset some time when you leave car over night it does not reset. The sometimes you get in car in morning and it has reset. I have mentioned this to dealer and get the response "Well never heard of that before"! Bottom line seems to be the car is what it is and dealers have difficulty accepting and correcting intermittent faults like this.

 

[Gomev]

You are having a terrible experience and have my sympathy. The only solution seems to be as you say reject car - good luck and please let us know how you get on.
Regarding the auto parking brake, I have the same issue. The auto hold should reset after every journey not matter how short the time between journeys - but it does not. It acts randomly. Sometimes when you pop to shops and leave car for few mins it does not reset some time when you leave car over night it does not reset. The sometimes you get in car in morning and it has reset. I have mentioned this to dealer and get the response "Well never heard of that before"! Bottom line seems to be the car is what it is and dealers have difficulty accepting and correcting intermittent faults like this.

Computers, and EVs are basically a computer on wheels, don't act randomly but according to their programming. Now of course we all know that bad programming can cause failures and unexpected results, however even the faults are usually consistent. We just need to find the pattern with documented results of what we did and the result, i.e. debugging.
I fortunately have not experienced Autohold disabling itself whilst driving or being at a standstill in the MG5 unless I have touched the throttle of course. It did turn itself off in the ZS but eventually I discovered I was accidentally pressing the button with my arm whilst resting it on the centre console!
Just guessing but does it reset to off at the time time as the current trip resets itself to zero ?

 

[Squidder]

Hi Everyone that might want an update. And even for those that don't!

Did not reject the car as MG started sorting themselves out.

2 weeks ago MG Gloucester took the car in and gave me an MG4 courtesy car (happy to talk about that elsewhere after a good long road test of that)

Phone call Thursday lunch time, service manager was a bit vague that they'd "swapped a module that involved removing the entire underside and battery" so having spoken to some mechanics that would mean..... They've changed the battery! Which was my original suspicion.

Took it out for an 80mi test drive and should be calling me to confirm collection the next morning... Mile 79 THE ERROR RETURNS! Hahah.

So my understanding so far is they've changed the BMS, the battery and still not found it haha.

I'm ok with waiting a bit longer as they gave me an electric courtesy car which with the miles I sometimes drive was the entire reason I got the MG5 but I'm having a little bit of schadenfreude as they were so convinced at the start it was an easy fix/software and I suspected not!


The mystery continues

 

[Alb]

Thanks for the update

 

[barry22]

I’m having the exact same problem with my 72 plate.

 

[barry22]