Another run away ZS EV?!

[Gadget Geek]

The ACC cancels as I have said many times. It's the radar that doesn't cancel when it is "locked on" to the vehicle in front which is decelerating at the time you touch the brake pedal.

1. Both cars at a constant velocity when brake pedal applied = ACC cancelled with radar cancelled.

2. Car in front accelerating when brake pedal applied = ACC cancelled with radar cancelled.

3. Car in front decelerating when brake pedal applied = ACC cancelled but radar still active.

Has anyone else noticed this behaviour?

 

[natasha y]

The ACC cancels as I have said many times. It's the radar that doesn't cancel when it is "locked on" to the vehicle in front which is decelerating at the time you touch the brake pedal.

1. Both cars at a constant velocity when brake pedal applied = ACC cancelled with radar cancelled.

2. Car in front accelerating when brake pedal applied = ACC cancelled with radar cancelled.

3. Car in front decelerating when brake pedal applied = ACC cancelled but radar still active.

Has anyone else noticed this behaviour?

For clarity, what happens if you push the lever fully forward to turn ACC off?

In any event I haven’t noticed this yet. I did notice regen not being used. Maybe I will see if I can replicate this in mine.

 

[GaryMG4]

Getting out of your car without hitting the stop button is not recommended, and the car will warn you if you do that.

the MG4 doesn't have a stop button, lust the parking brake and the big P on the drive knob. FWIW you can apply the park brake and leave the car in drive, using the drive knob P works like an ice autobox, puts it in neutral and engages the pawl to lock the drive and applies the parking brake.

 

[fred12345]

Not so! My damn MG 4 took off after I stepped out of it, having put it into Park, with the confirmation lights illuminated, and the door open.

From memory, there is a warning in the manual for ZS not to leave the car if it's in ACC mode and step out as it will move on. Could it be P was not in park (red light) but in auto-hold (green P) and the car was not turned off? If you can recreate the same thing happen again, then the MG garage would be able to find the fault.

 

[fred12345]

When you brake or disengage the ACC, the ACC does disengage and the car slows down.

good so far

However, if you brake or disengage the ACC when the radar is "locked on" to the car in front, if that car is slowing down, my car slows down with it without the expected regenerative braking.

maybe it's because of the split timing between actions (brake, locked radar, ACC) that the car decides that the safest thing is to continue to keep the safe distance from the car in front for which regenerative slowdown is less safe than the car applying traditional brakes?

If you brake or disengage the ACC before the car in front starts to slow down, then regenerative braking kicks in and my car slows down on its own, regardless of the car in front.

yes, definitely sounds like getting the right timing and the car deciding it's safer to use brakes than regen ...

Thanks for detailed explanation.

 

[fred12345]

3. Car in front decelerating when brake pedal applied = ACC cancelled but radar still active.

2 things possible, 1- timing between turning ACC off and the car in front slowing down - if you turn ACC off after the radar started using brakes to slow you down, my guess is that radar takes priority over ACC and regen braking (as it should logically be, for safety)

2- is there a setting on your car like pedestrian (but in this case car) emergency stop or distance keeping that works regardless of ACC being on or off? so maybe you trun ACC off but the car decides it needs to slow you down (brakes being safer and faster than regen)?

 

[Gadget Geek]

I did some experimenting yesterday and found it's the sensitivity of the brake pedal. If I tap the brake to try to disengage the ACC, sometimes it isn't enough to register the pedal has been touched.

Also, the main culprit for the radar not disengaging is when I read the road ahead and see traffic slowing, I tap the ACC stalk forward to disengage the ACC and coast using regen. However, if it detects the vehicle in front slowing, it will keep the radar on and use that to slow down rather than the regen. It obviously doesn't trust me to do it on my own, thinking I might coast into the back of the vehicle in front.

 

[m4rmite]

I know of a new zs ev that's ploughed into a building

Driver was touching 80yrs old and it was a new car under the mobility scheme.
I've been waiting for the story to break on msm.
All involved were OK injury wise, which is the main thing.

 

[fred12345]

All involved were OK injury wise, which is the main thing.

Good that they were all OK. My guess is that it was the first EV they had and maybe even first automatic ...