MG4 Reduction Gearbox Broken (first in the World???)

[capitan capete]

Hello, it's been a while since I said anything regarding this case.

Well, now I have a new engine, the consumption is the same.

updated to version r46.

but from time to time I have an engine stop.

Sometimes the engine failure light comes on and tells you to stop safely.

and other times the fault does not come on and disconnects the battery.

To restart the first gear I disconnect the 12v battery

other times just closing and opening doors resets the ECU

Loading speed seems to have improved but sometimes I have a significant drop.

Regarding the engine breakage, Saic tells me that there are suspicions that they have intentionally removed the oil. It seems that they didn't know that I complained after 2000 miles that I lost a lot of oil and the level was not restored during the service visits.

If I continue to have problems I will have to go through judicial means I hope that is not the case and that the brand assumes its part of the responsibility

greetings

 

[capitan capete]

The first photo is the first engine failure and the second is more strange, I don't have the battery percentage and it says that the battery is charging...

 

[tsedge]

Hmmmm.... you should not be getting motor faults (obviously) and given the bad experience you've already had with this car, I would recommend you ask for the car to be replaced - so they can fix the issues properly on someone else's time.

 

[spence7788]

Hello, it's been a while since I said anything regarding this case.

Well, now I have a new engine, the consumption is the same.

updated to version r46.

but from time to time I have an engine stop.

Sometimes the engine failure light comes on and tells you to stop safely.

and other times the fault does not come on and disconnects the battery.

To restart the first gear I disconnect the 12v battery

other times just closing and opening doors resets the ECU

Loading speed seems to have improved but sometimes I have a significant drop.

Regarding the engine breakage, Saic tells me that there are suspicions that they have intentionally removed the oil. It seems that they didn't know that I complained after 2000 miles that I lost a lot of oil and the level was not restored during the service visits.

If I continue to have problems I will have to go through judicial means I hope that is not the case and that the brand assumes its part of the responsibility

greetings

Thanks for updating,

Glad to hear you’ve got it back but sorry to hear it’s not 100% yet, might not help but you never know, I’ve heard of one other drive unit failure that was replaced under warranty. I believe he had similar HV battery disconnection problems after which was resolved by software as instructed by SAIC, presumably a drive module update to match the new unit or some such, it was on one of the MG4 Facebook groups.

Hopefully the dealer sends it to MG technical in China I presume & they get back to you quickly and get it resolved, this is probably what they may do but may speed things up if they have a possibility, unfortunately the problem seems to be waiting on SAIC getting back to dealers with problems out of the ordinary like this, not the way it should be unfortunately & surely a drive unit change for whatever reason should be in a workshop manual fully with software info etc. to avoid problems.

Sorry for rambling ? & good luck with it!

 

[Rolfe]

I think you need to update your profile details, as your car is a Trophy and your profile says SE SR.

 

[kaneka]

I have a similar experience with my new MG4 (bought it on August 2024) in Indonesia and after 1 month using it, the warning light (Motor Fault Consult Handbook) turns on and off (only mine had a yellow colored warning light).
The MG Authorized Repair Shop tried to scan and updated the firmware and it stopped showing the warning lights, but after 3 weeks it showed again. And the warning light keep turn on and off and the motor sound was very rough. Seemed like the regenerative braking wasn't fully disengage and sound like mechanical buzzing.
At last the motor stopped working, it wouldn't move forward or reverse. And my car had to be towed to MG repair shop.
They observed and scanned and end up with the conclusion that the motor had to be replaced with the new one (complete with reduction gearbox and the IMCU), but unfortunately i have to wait for another 2 months for shipping the parts from MG Shanghai, China. Thankfully it came with warranty and they provided me with courtesy car (also a MG4) until they fixed it.
I hope they replacing with the motor that doesn't have the same problem. Fingercrossed

 

[Tuareg]

How many MG4s have been sold and how many have had a motor problem like this? Me thinks not much more than a handful, same as any other relatively new model of any other car. This is what the warranty is for and it looks like MG is honouring these claims without much question at all.

 

[tsedge]

Hardly any I think, second one I have heard about.

 

[Han51]

How many MG4s have been sold and how many have had a motor problem like this? Me thinks not much more than a handful, same as any other relatively new model of any other car. This is what the warranty is for and it looks like MG is honouring these

 

[Ian Key]

I collected my brand new MG4 trophy on Wednesday and they said a fault would pop up but it was just a data fault and it should clear up in a few days as they had just updated it. Left the dealership and immediately on 50mph bypass, noticed the acceleration did not seem the same as when I test drove their demo car. This motor fault consult handbook popped up and then another message saying "power limited, speed limited" with a little turtle icon. I could not go any faster than 13mph. Managed to make it safely to a car park and then I had a family member follow me back to the dealership (where I was lucky if I was gojng 6mph) as they wanted me to call AA and be recovered (even though I had owned the car for 10 minutes!) I have heard nothing regarding my car since about what has caused this, if it is fixable, how long it make take etc. Currently have their demo car to drive around but I am concerned now as I have paid for the car and it has taken the shine off for me a little bit as I was very excited.

It sounds like they knew there was a fault with it before selling it to you. I'd give then the option to either replace the car with another brand new one or a full refund as you are rejecting the car.

 

[Tuareg]

1st post woes again, just sayin'

 

[LenEV2016]

1st post woes again, just sayin'

Must be a troll then!

 

[Tuareg]

Might well be, been a few on here in the past

 

[LenEV2016]

Might well be, been a few on here in the past

Yeah everyone that comes on here and posts about a fault with their first post must be a troll.

It can't be that they have a genuine fault, cars have faults, the MG 4 has had a few, for the most part (in the UK) MG customer service is poor so their gripe may be genuine.

Car forums of all brands are littered with people complaining but this one makes me laugh, there are those who see it as an obligation to defend MG and have a pop at new members if they look to complain

 

[Tom900]

View attachment 19704View attachment 19706

hi can I ask you what was the result MG take responsibility for that?

 

[nexia201]

So shit happened to me today without any warning .

My car is a Trophy long range, it's a cab so has 196,000 km. I did an oil change at 60 000k at the dealer (which I doubt they did as it was on my instructions) then at 120,000 km I did it (and found a lot of swarf around the magnet bolt) then I did it again at 180,000 km and this time I found a leak in the passenger side oil seal. The reduction gear had aprox 600/700 ml left in when I emptied the oil, so I ordered the seal filled with oil and continued to work with car.

Today was driving normally doing 20 kph in a very narrow road but with a bit of incline and Boom and car lost drive! I knew what had happened but not without any noise or indication that its going?? I just purchased a whole unit from a breakers in the UK, I hope it will not have similar issues. Our warranty as it's a cab was 100,000 km or 2 years which both are out by now. Car has been faultless until now.

PS: if anyone can help tell me the way to bleed the coolant system once it's changed, and if it will need any coding if I'm changing the complete unit. Thanks in advance.

 

[Tig170]

There is another one which has done over 100k miles (just cant find the link) with a similar issue, the gearbox is limited to 100k miles, as to what appears, but at least you've got another one 2nd hand for sensible money? - the coolant system is not an issue albeit in the UK, never seen it above 30 degs., so just drive sensibly and refill as and when necessary.

 

[nexia201]

There is another one which has done over 100k miles (just cant find the link) with a similar issue, the gearbox is limited to 100k miles, as to what appears, but at least you've got another one 2nd hand for sensible money? - the coolant system is not an issue albeit in the UK, never seen it above 30 degs., so just drive sensibly and refill as and when necessary.

Yes got a sub 3k miles one for £1450 posted to uk , then will pay €275 shipping to Malta

 

[Macadoodle]

So shit happened to me today without any warning .

My car is a Trophy long range, it's a cab so has 196,000 km. I did an oil change at 60 000k at the dealer (which I doubt they did as it was on my instructions) then at 120,000 km I did it (and found a lot of swarf around the magnet bolt) then I did it again at 180,000 km and this time I found a leak in the passenger side oil seal. The reduction gear had aprox 600/700 ml left in when I emptied the oil, so I ordered the seal filled with oil and continued to work with car.

Today was driving normally doing 20 kph in a very narrow road but with a bit of incline and Boom and car lost drive! I knew what had happened but not without any noise or indication that its going?? I just purchased a whole unit from a breakers in the UK, I hope it will not have similar issues. Our warranty as it's a cab was 100,000 km or 2 years which both are out by now. Car has been faultless until now.

PS: if anyone can help tell me the way to bleed the coolant system once it's changed, and if it will need any coding if I'm changing the complete unit. Thanks in advance.

when you say 'boom' what was the failure? casing blew out ? Makes me think that a 40k mile oil change might be a good preventative job on these reduction boxes.
I also don't tend to use full acceleration just for the hell of it as I think the casing is pretty thin from the pics I've seen, might not cope with high axial load long term.

 

[Tuareg]

Sounds like as the OP mentioned that the dealer missed an oil change, so can't blame MG for this failure. The casings will be well within their design envelopes to handle the power and torque of these motors. It could also have well been a faulty part from the factory, happens to all makes and models. Lots of MG4s with similar or higher mileages as they are a popular model for taxi service in many countries and no other reports of anything similar.