Interesting/worrying story from Scotland - ZS with no brakes.

[Tommy]

Genuinely interested to know would this be possibly what causes the car to shoot forward ... lightly press brake pedal to select drive, but also slightly catch the accelerator by mistake thereby in effect pressing both pedals ... the brake is not applied enough to stop the car moving forward, and yet the accelerator is applied enough to urge the car forward, especially in an EV with instant torque?

 

[DB Go Rex]

5 modules. I have posted the report.


Ive posted the results. Snide comments dont help. I have a life to live, I dont spend all day on forums answering to sceptics.


Ive posted the reply. I dont spend all day on forums. I have a life and am in the process of dealing with the lease company and MG so dont have time for stupid comments.

Did they reset these fault codes and then test the car?

The reason I ask is that I wouldn't be surprised if the the average ZS reports a lot of these on a regular basis. Particularly as it often disabled the collision systems due to wonky data it has received. They aren't necessarily going to cause full failure of a braking system.

I'm not sure there is much in that lists that would definitely point to braking failure.

 

[Tommy]

Another take on this surge forward issue ... this morning, after heavy rain overnight the brake discs were a bit 'seized'. Pressing the accelerator lightly did nothing so I pressed a bit harder, when the brakes 'unseized' themselves the car was suddenly moving forward enthusiastically ... just a thought ... same would apply if there was a slight obstruction to the wheels such as a kerb or similar obstruction.

 

[johnb80]

Early on with my MG4 I did have cases of poor braking when in ECO mode. Occasionally I would press the pedal and nothing would happen until I really pushed hard. I always drive it in SPORTS mode these days (partly for the better braking response) and I haven't had this happen for a long time, so it may have been fixed in a software update (my car has had a ton of these now). But it is conceivable this could catch someone out in the wrong circumstances.

Note you said POOR braking not accelerating away, I agree it may catch people out not getting the response they've become accustomed to but in this instance it was at parking speeds and then allegedly accelerating away so I don't see how this can apply in this instance.

Another take on this surge forward issue ... this morning, after heavy rain overnight the brake discs were a bit 'seized'. Pressing the accelerator lightly did nothing so I pressed a bit harder, when the brakes 'unseized' themselves the car was suddenly moving forward enthusiastically ... just a thought ... same would apply if there was a slight obstruction to the wheels such as a kerb or similar obstruction.

But not with your foot on the brake pedal!

 

[tsedge]

Note you said POOR braking not accelerating away, I agree it may catch people out not getting the response they've become accustomed to but in this instance it was at parking speeds and then allegedly accelerating away so I don't see how this can apply in this instance.

I'm simply using it as an example of bugs in this area, if there are problems with brakes there might be problems with acceleration too as it is now a blended system with regen.

No, I have never had the car accelerate when it shouldn't and I agree that it is possible (even likely) it is wrong pedal being pushed.

The MG4 (which is what @tsedge has) does not have a servo, it has a computer-controlled pump that does the actual braking, the pedal is not normally directly connected to the brakes themselves. So you can alter the brake pedal force required quite easily in different modes.

Exactly. This is not a conventional powertrain either on the motor or brake side.

See, for example, your informative post:

Brakes and ABS on the MG4

The 4 does not appear to have a conventional separate ABS system as we know it. Everything goes through the IBS (Intelligent Brake System) including the wheel speed sensors. The only way I can see it achieves ABS (and traction control) is by activating a pair of inlet and relief valves on each...

www.mgevs.com

 

[Tim Green]

What mg4mc describes is actually a good description of a servo. Obviously not the usual car servo which just "helps" pedal effort. I suggest the move to effectively computer control is NOT a good idea, and I am surprised it has been allowed by the certification authorities. All that is separate from the idea of diminishing the retardation effort on the basis of eco or any other mode of operation of the car. There is no logic in that approach. I am glad I have not purchased an MG4 and will give them a wide berth.

 

[MickeySw]

What mg4mc describes is actually a good description of a servo. Obviously not the usual car servo which just "helps" pedal effort. I suggest the move to effectively computer control is NOT a good idea, and I am surprised it has been allowed by the certification authorities.

Should not come as a surprise ‘Fly by wire’ is well established in commercial airliners since the 80s where one would think a higher grade of certification is applicable?

 

[Nelly]

Did they reset these fault codes and then test the car?

The reason I ask is that I wouldn't be surprised if the the average ZS reports a lot of these on a regular basis. Particularly as it often disabled the collision systems due to wonky data it has received. They aren't necessarily going to cause full failure of a braking system.

I'm not sure there is much in that lists that would definitely point to braking failure.

They told me everything had now been reset. It also had an update lsdt year when it was serviced due to a recall that i never got. They didnt mention what it was on the service report though.

Seemingly you have time to make plenty.

Not a single fault there that could be considered dangerous nor would they cause uncontrolled acceleration, nothing life threatening. DVA wont be interested, nor will any of the other authorities.


Comms faults recognised and dealt with appropriately (fail safe). It certainly wont cause out of control acceleration / no brakes / runaway.

 

[Tim Green]

Commercial airliners have multiple support computers, not just one. Even so, pilots will tell you that it is common to have to shut down the computers whilst on the tarmac to get rid of obvious errors. Reading this forum indicates that the MG software is riddled with problems and I would not like to think of it being in control of the brakes. I am worried enough about the ZS brakes which can apply the brakes, although one hopes not over-ride the brake pedal.

 

[JimD]

Wow, a youtube video saying your EV is going to kill you! Well I'm convinced.

 

[Verdigris]

Especially one about the made-up story that inspired this thread.

 

[tsedge]

What mg4mc describes is actually a good description of a servo. Obviously not the usual car servo which just "helps" pedal effort. I suggest the move to effectively computer control is NOT a good idea, and I am surprised it has been allowed by the certification authorities. All that is separate from the idea of diminishing the retardation effort on the basis of eco or any other mode of operation of the car. There is no logic in that approach. I am glad I have not purchased an MG4 and will give them a wide berth.

The logic is simple: in ECO mode you want to promote smooth driving so a diminished effect on the brake and throttle (at least the first part of the travel) is exactly what you want.

The MG4 is great. I love mine.

Oh dear. This isn't helping your case. Now you risk losing the people who were willing to give you the benefit of the doubt.

 

[DB Go Rex]

Please don't post links to this guy.

He and his YouTuber friend are basically making an industry of conspiracy theories and FUD.

Don't fuel the fire.

 

[Tim Green]

Smooth driving is achieved using the accelerator, not the brakes. If you are smooth driving, you rarely use the brakes. But they should be there in full effect if required.

 

[johnb80]

Jesus Nelly, you should know when toi stop, this one has been debunked to death all over the net. Amazing how this death defying trip rammed into a police van and yet there was no damage to either vehicle? How the driver fighting with the runaway car could phone his partner to keep other road users out of the way and the police to come and help. It's really odd that when he finally rammed into the police van the terrifying ordeal came to a stop (phew), any EV that is help in a stalled condition (motor being commanded to go but stopped from doing so) will rapidly overheat with potential fire as a possibility.

Really?

And guess what, if this was true, dont you think something would have been done about it? especially as so many police officers were involved? No recalls, no massive publicity other than the original story.

 

[Gadget Geek]

Jesus Nelly, you should know when toi stop, this one has been debunked to death all over the net. Amazing how this death defying trip rammed into a police van and yet there was no damage to either vehicle? How the driver fighting with the runaway car could phone his partner to keep other road users out of the way and the police to come and help. It's really odd that when he finally rammed into the police van the terrifying ordeal came to a stop (phew), any EV that is help in a stalled condition (motor being commanded to go but stopped from doing so) will rapidly overheat with potential fire as a possibility.

Really?

And guess what, if this was true, dont you think something would have been done about it? especially as so many police officers were involved? No recalls, no massive publicity other than the original story.

I'm surprised he didn't claim the car would explode if it went below 50 mph.

 

[johnb80]

I'm surprised he didn't claim the car would explode if it went below 50 mph.

Now maybe theres a film idea in there somewhere, I'm sure he will be developing it

 

[Susanna]

Surely, if any of these ‘experiences’ were substantiated, the DVSA would have taken action.

 

[johnb80]

Surely, if any of these ‘experiences’ were substantiated, the DVSA would have taken action.

Of course, without a doubt, especially if a police vehicle had to be rammed into to stop it. A short time after the Brian Morrison incident there was a runaway Jaguar I-Pace on the M62, again the police were involved in this terrifying ordeal. That driver was arrested and spent a couple of nights in the cells before prosecution.

 

[tsedge]

Smooth driving is achieved using the accelerator, not the brakes. If you are smooth driving, you rarely use the brakes. But they should be there in full effect if required.

I assume this is a reply to me?

The brakes are available in full effect but you have to push harder in ECO mode to get that effect. It just modulates the curve of effectiveness of the pedal, it doesn't change the maximum braking available.

Anyway, this is how it works, however surprising it may be.