Sudden automatic braking issue (merged, MG4)

[Matt x power]

It kicked in for us when reversing into a parking space in a car park adjacent to a road. It must have seen the passing traffic and braked.

That's happened a few times now and each time, the braking is so severe, it feels like we've hit something.

Mine did this too, I set it to alert only

 

[NLMGSAN]

Mine did this too, I set it to alert only

Well... two weeks ago it saved me from hitting a biker that suddenly decided to cross my path by going in the wrong direction. I was concentrating on cars an bikes coming from the other side and I never saw him.

 

[Rufus2005]

I've always turned off lka and front collision assist but since my software got updated last week I have left it on. All good until today when it suddenly slammed the brakes on. Now I understand when people mention this issue, its not like I've had before when you can override it with the accelerator pedal, this literally locks the brakes dead. Luckily I was going quite slowly and nothing behind me. It's disabled from now on lol

 

[NLMGSAN]

I've always turned off lka and front collision assist but since my software got updated last week I have left it on. All good until today when it suddenly slammed the brakes on. Now I understand when people mention this issue, its not like I've had before when you can override it with the accelerator pedal, this literally locks the brakes dead. Luckily I was going quite slowly and nothing behind me. It's disabled from now on lol

You are on R59?

 

[Rufus2005]

You are on R59?

Yes sure am

 

[Rolfe]

I've always turned off lka and front collision assist but since my software got updated last week I have left it on. All good until today when it suddenly slammed the brakes on. Now I understand when people mention this issue, its not like I've had before when you can override it with the accelerator pedal, this literally locks the brakes dead. Luckily I was going quite slowly and nothing behind me. It's disabled from now on lol

It's your choice, but I don't think "LOL" is an appropriate frame of mind in which to be making that decision. You wouldn't be laughing if you hit something or someone the system could have prevented you from hitting.

 

[Rufus2005]

It's your choice, but I don't think "LOL" is an appropriate frame of mind in which to be making that decision. You wouldn't be laughing if you hit something or someone the system could have prevented you from hitting.

I wouldn't be laughing if unnecessarily it emergency braked and someone hit me up the backside either. I've had many years of driving behind me and never needed help from the car to brake.

 

[FrancisM]

I've not had this happen yet, but have only around 300 miles on the clock. The AEB sensitivity defaults to moderate in my car. I'll try setting it to low and see if it remembers the setting.

I'm reluctant to disable it in case it does help to avert injury or damage. One scenario is pressing the wrong pedal i.e. hitting the accelerator when intending to hit the brake. This seems to be a common cause of accidents in automatics and possibly more so in electric cars with their instantaneous low down torque.

 

[YaR]

Set the AEB sensitivity to low. This setting stays set and only brakes if absolutely necessary. No phantom braking with sensitivity set to low. ?

It's set to low and it still happens. Happened before the update, happens after the update but more often. I've had dozens of false positives but zero real incidents. With a ratio like that the rational thing to do is turn it off given a sudden stop on a road is a risk to other drivers, especially when crossing lane markers.

 

[AndyL61]

It's set to low and it still happens. Happened before the update, happens after the update but more often. I've had dozens of false positives but zero real incidents. With a ratio like that the rational thing to do is turn it off given a sudden stop on a road is a risk to other drivers, especially when crossing lane markers.

That's suggesting then that 2 different cars have completely opposite behaviours even when using the same settings , that is worrying and should ring alarm bells to MG. My Trophy has done over 27k miles in short of 2 years and has never done an emergency brake unless there was good reason. I set the sensitivity to low and it stays set even if the system is rebooted via holding the home button. I'm glad that my car behaves in this way but makes you doubt getting another one that may behave completely differently.

 

[NLMGSAN]

That's suggesting then that 2 different cars have completely opposite behaviours even when using the same settings.

Yes.
All these systems rely on sensors. And they can be off/poorly calibrated. Moreover, some of us with the same car and using it in a similar way and with apparently the same software (like R59), could in fact be using different code that makes these systems tick. And as circumstances (road, weather, traffic) can influence the way these systems work (or rather, not work), you get tons of variations in car behaviour you may not expect.
MG does not have the factory QQ to tackle this, nor do they have services in place to correct them after delivery.

 

[YaR]

That's suggesting then that 2 different cars have completely opposite behaviours even when using the same settings , that is worrying and should ring alarm bells to MG. My Trophy has done over 27k miles in short of 2 years and has never done an emergency brake unless there was good reason. I set the sensitivity to low and it stays set even if the system is rebooted via holding the home button. I'm glad that my car behaves in this way but makes you doubt getting another one that may behave completely differently.

Well yes, the behaviour changed after the 1 year service updates, so we're almost certainly looking at software version behavioural differences.

 

[FrancisM]

That's suggesting then that 2 different cars have completely opposite behaviours even when using the same settings , that is worrying and should ring alarm bells to MG. My Trophy has done over 27k miles in short of 2 years and has never done an emergency brake unless there was good reason. I set the sensitivity to low and it stays set even if the system is rebooted via holding the home button. I'm glad that my car behaves in this way but makes you doubt getting another one that may behave completely differently.

Just checked mine (SE LR) and it doesn't remember the AEB sensitivity setting. It defaults to moderate. (The LKA defaults to low sensitivity.)

The pre-flight settings are becoming ridiculous. I now do (LKA disabled, AEB low sensitivity, traffic sign recognition disabled, ECO drive mode, adaptive regenerative braking, auto headlights off). And that's before any AC adjustments. Remembering all that is becoming challenging.

 

[Rolfe]

I've never changed the setting, and the car only did an emergency stop once, when there was good reason. I think there might have been another time when I was coming up behind a stationary car and I hit the brake at the same time as the AEB happened. over 14,000 miles and it's not something I ever think about. I don't think it's happened at all for over a year.

 

[Rufus2005]

I've never changed the setting, and the car only did an emergency stop once, when there was good reason. I think there might have been another time when I was coming up behind a stationary car and I hit the brake at the same time as the AEB happened. Over 14,000 miles and it's not something I ever think about. I don't think it's happened at all for over a year.

I never thought about it either then one day it happens, not something I want a repeat of.

 

[Cocijo]

These systems can of course get it wrong - sometimes with very bad results. I know from the early days of Tesla ownership how frightening phantom emergency braking was on early cars.

The other side of the coin is that these systems can also expose poor driving that has gone unnoticed for years - which is a good thing, but very hard to convince the driver that they need to modify and improve how they drive!

Many drivers approach hazards far too fast, and have probably got away with it for years, until one day they don’t.

The systems today are still developing, as all good safety systems should and are not perfect, but instead of instantly blaming the software it’s worth taking a full and honest review of what happened and why. This can be harder than you think.

Many drivers have no idea how bad their driving actually is and assume that they are a good driver without having any evidence other than their own opinion!

 

[NLMGSAN]

Surely some drivers have no clue what they are doing. But that doesn't make it less irritating when the systems really fail. I'm sure you agree.

 

[Rolfe]

I never thought about it either then one day it happens, not something I want a repeat of.

Was there any apparent reason for the behaviour? I was reassured when I realised the car had seen a pedestrian apparently about to walk out in front of it. This was May 2023, no repeat.

 

[Rufus2005]

Was there any apparent reason for the behaviour? I was reassured when I realised the car had seen a pedestrian apparently about to walk out in front of it. This was May 2023, no repeat.

I was pulling up behind a car waiting for another car to pass the other side of the road, but it emergency braked completely out of all proportion.

 

[Rolfe]

Maybe something needs calibrating? When I do that all I get is a message on the driver's screen and a beep.