ESP System

[dervmerc]

Hi Guys, I wonder if anyone can give me operational details on the ESP system? Not had my C class 220 cdi coupe long.After I bought it there was no trouble but the first time I drove it in the wet I nearly lost the back end on a roundabout.I then found if I accelerated fairly quickly it was very twitchy at the back.

I thought the system might of been switched off so after reading the manual I switched the dash switch to "on" position. I later noticed when it was damp that the amber triangle light came on when I accelerated and wondered if it was a warning to say it was off! I found a site about this complex system and it said the warning triangle comes on when the system intervenes and makes corrections.Can anyone confirm if that's true and how do others find how the system work? I'm getting used to it and it keeps you alert but I've never owned a car which seemed so unstable in the wet.

 

[DougCLK320]

The default status is "ESP on", at least it is on my A209 CLK. Every time you re-start the engine, ESP is automatically "on".
The warning triangle flashes occasionally, but only as the car struggles for grip under acceleration.
If you switch the ESP "off", the warning triangle lights continuously - to warn you that it is switched off.
I have read elsewhere that Mercedes Benz, for safety reasons, have engineered the system to still work a bit, in the background, whilst switched off (in extreme conditions) i.e. you can't "fully" switch off the ESP, but that might just save your life !!!!!
Doug

 

[dervmerc]

Thanks for that Doug. It makes me wonder if a sensor became faulty, how the system would react. I expect a warning light would inform you if that happened? I think I must be between getting used to the fact the car can take over and the strange sensation that provokes!

 

[jberks]

If it detects a fault - and it is very sensitive, it will put the light on permanently so I imagine it's working fine.
It will intervene on acceleration if you're spinning the wheels and flash the light - which is the easiest way to tell if its working - should you want to.
You should find that it will allow a little bit of slip as people complain they intervene too readily but it will not allow things to get out of hand. If it detects anything untoward, even if you are coasting, it will intervene. Mine kicked in once on a flooded road at 60mph - I'd already backed off but the back end went light and twitched and the light came on straight away and it settled down immediately. Very clever gizmo.
I wonder whether your problem adjusting has anything to do with your previous cars. Were they all front wheel drive? RWD is very different if you're not used to it. With fwd - overcook the throttle on a corner and it will understeer. On a rwd it will do the exact opposite. Odd sensation initially but you soon adjust your driving to it and as any car expert will tell you, rwd is better.

 

[rf065]

I'm getting used to it and it keeps you alert but I've never owned a car which seemed so unstable in the wet.

You might want to check your tyres are up to scratch or maybe if the road had oil or diesel on it? It really shouldn't feel unstable in normal driving.

Russ

 

[dervmerc]

If it detects a fault - and it is very sensitive, it will put the light on permanently so I imagine it's working fine.
It will intervene on acceleration if you're spinning the wheels and flash the light - which is the easiest way to tell if its working - should you want to.
You should find that it will allow a little bit of slip as people complain they intervene too readily but it will not allow things to get out of hand. If it detects anything untoward, even if you are coasting, it will intervene. Mine kicked in once on a flooded road at 60mph - I'd already backed off but the back end went light and twitched and the light came on straight away and it settled down immediately. Very clever gizmo.
I wonder whether your problem adjusting has anything to do with your previous cars. Were they all front wheel drive? RWD is very different if you're not used to it. With fwd - overcook the throttle on a corner and it will understeer. On a rwd it will do the exact opposite. Odd sensation initially but you soon adjust your driving to it and as any car expert will tell you, rwd is better.

Thanks for your assessment.Yes you're correct.It's been quite a while since I've driven RWD cars.I seem to of settled better now but it was a strange experience and I was unsure of the cars stability in the wet.I did'nt overdo any acceleration or take the roundabout too quickly,I was just in the inside and the camber was bad but without a quick response the back end felt as though it would of slewed right round.I thought the ESP would of stopped that hence my confusion.I'm now more cautious in the wet and I guess that can only be a good thing!

 

[dervmerc]

You might want to check your tyres are up to scratch or maybe if the road had oil or diesel on it? It really shouldn't feel unstable in normal driving.

Russ

The low profile tyres are all the same make and in good condition with plenty of tread.It's difficult to say if there was oil on the road but just accelerating reasonably quickly,not flooring it, the back end twitched as though it was struggling for grip.The tyres are the tread pattern with a central groove and the grooves in the tyre arc from the centre to the outside edge. I prefer a more conventional tread pattern and it may be these tyres are not the best for the car.A merc indie told me that the humming/whine noise from the rear axle area was probably the tyres.