Unusual and potentially fatal ABS/ESP Issue

[bybuys]

Hi All
Its been a long time since I've been on the site as I garaged my 230CLK convertible as I was too embarrassed to drive it because of the severe rust around the wheel-arches, headlamps and boot lock. Covid has given me the time to do the repairs and I have had a great year of trouble free motoring as is passed MoT without fault, after sitting for 5 years! I dad another MoT done 2 days ago and again passed without fault...but here is the problem.

I understand the ABS/ESP system, its purpose and how to reset it but yesterday I drove to Selby which is about 130 miles. I had done about 115 miles and was on a single lane carriageway when they was a sudden 'bang' type noise, my steering yanked violently hard right and the ABS/ESP illuminated. The car and steering returned to normal in a split second and drove normally as if nothing had happened for the rest of the journey, but with light still on. I was very fortunate there was nothing coming towards me as the jolt to the right was severe enough to take me over the centre white lines. It was quite a shock and I continued very carefully. At my destination, and without further issue (but with the light still on) I turned off the ignition and restarted the car fully expecting the ABS/ESP light to be on. In fact I might have been happier if it was on as it would be clear that I still had an issue to resolve... but the light extinguished and all appears normal? I have driven 15 miles this morning, light remains out and no sign of any problems. Does anyone have any thoughts or experienced a similar ABS/ESP failure to cause such a severe, potentially life threatening issue. as I have the return journey on Sunday and am feeling very wary. Thanks all in anticipation.

 

[Doodle]

It assumes that the ABS/ESP light was the cause of the bang and the steering feedback, whereas its just as likely (if not more so) that it was a result of that activity.

You don't mention whether you were braking at the time, but it sounds like you hit something in the road and the rapid unintended movement upset the ESP system. Turning the car off and on again resets the system, it checks if the fault condition is still present - it wasn't so the light went out.

 

[bybuys]

Thanks for the response. I wasn't braking at the time and had my eyes on the road. I certainly didn't see anything in the road but I suppose it is possible. It remains fine at the moment so hopefully you are right about the cause. Thanks again.

 

[Petrol Pete]

Hitting an unseen pot hole will do this. Have you had a good look under the car , inner wheel rim and tyre etc ?

 

[DSM10000]

You are blaming a system that cannot cause what you are describing.

The ABS/ESP systems act independently or in unison depending on the situation.

I have never heard a "bang" when ABS OR ESP has operated and neither system can directly provide input to the steering.

As others have said, you must have hit a pothole or similar and this caused the steering input.

 

[OneForTheRoad]

Sounds like you ran over a tarmac mole, quite common on rural stretches I hear ..

 

[ernie]

What about a spring breaking suddenly?

Ernie

 

[m80]

The ESP remaining on has me thinking there will be a recorded fault.

The ESP activates brakes, where it sees a wheel has lost traction it activates the diagonally opposite brake. But the ESP light will flash and then extinguish as the situation returns to normal.

A possibility I see is that the system saw lost traction, applied the fr o/s brake, and pulled you in that direction.
It then looks, to me, as though the system recognised a system issue and the light remained on.

I don't mind those with better knowledge telling me I'm way off, but for me I would get the codes read.

 

[bybuys]

Many thanks for all your responses. I had a quick look under but could see nothing but will do so more thoroughly and report back

 

[bybuys]

Hi Again
Having received the responses to my original post I began to doubt myself and whether I was paying full attention when driving, to have potentially hit a pot hole and not seen it. Anyway, car has had little use other than running about and there have been no issues. However, today did 280 mile round trip to Poole. After 91 miles of trouble free 'roof down' driving an identical thing happened. Driving 70ish on A34 dual carriageway in clear conditions when, without me applying the brake and for no obvious reason, the brakes seemed to being applied hard automatically and car pulled fairly significantly to the right (it never does normally under braking). The Orange triangle in the centre of instrument panel came on briefly and, as it extinguished, the BAS/ESP light came on. I continued to destination trouble free. When I restarted the car the BAS/ESP had reset and no lights showed.

On the return I turned off the ESP and the orange triangle on dash was illuminated as I drove. I drove for 40 miles and the same thing happened despite ESP being off. The pull right was not as significant as I was only doing about 50. The orange triangle went out and the BAS/ESP came on and remained on for the rest of the journey.

One thing I did notice after both events on both journeys today was that footbrake did not have its usual soft and efficient feel...it felt that I was having to push harder to brake and got more feedback through the brake pedal.

Any thought on what is going wrong would be appreciated. I suspect it will be off to the Indy next week but just wanted and further ideas before hand.
Thanks

 

[markjay]

There's clearly a fault with the suspension or brakes that caused the ABS and ESP to disengage.

I wouldn't consider the car safe to drive until the suspension and brakes were thoroughly inspected, and the fault codes read.

But the ABS and ESP disengaging due to 'implausible date input' - or due to a reported failure of a system it depends on - is expected behaviour, and its purpose is to prevent the ABS and ESP from incorrectly interfering.

 

[Bellow]

All I can add to this is that ESP intervention (on a short wheelbase car at least - smart) will be abrupt - borderline brutal - with the forces it exerts on the car.

 

[Petrol Pete]

I really think you should not drive this car. You have written on a public forum that it is behaving in a potentially fatal manner. The chances of it throwing you into the path of another road user is slim but the fact that you are aware of the fault would not put you in a good place in a court of law if it did.

Park it and find the fault.

Sorry to be so negative but we live and drive in that world these days.

 

[st13phil]

I really think you should not drive this car.

+1

Apart from the risk of injury it represents to you and other road users, driving a car in a mechanically dangerous condition can result in a Dangerous Driving charge (which carries a potential custodial sentence) for a very good reason.

It's one thing driving it the first time it happened, and quite another to continue to drive it without the issue being resolved.

 

[Bellow]

I really think you should not drive this car. You have written on a public forum that it is behaving in a potentially fatal manner. The chances of it throwing you into the path of another road user is slim but the fact that you are aware of the fault would not put you in a good place in a court of law if it did.

Park it and find the fault.

Sorry to be so negative but we live and drive in that world these days.

You have a point.
I had unwanted ESP intervention on my smart during cornering a few times and it was extremely de-stabilising.
New rear tyres when the fronts were quite worn but not ready for replacement was the cause - the difference in rolling diameters confusing the ESP.
I also had it trying to correct non intrusive understeer due incorrect steering toe after hitting a deer deranged the steering slightly. The steering wheel angle being out of kilter with lateral G readings confused the ESP. It only chopped the throttle then. Individual brake application is for oversteer correction and as I've said, is pretty brutal (but very effective!).

The guys who had accidents with their Roadsters had them when they naturally corrected the slide - then the ESP jumped in.

In all the above, the causes were external and 'mechanical' in nature - not electronic. I'd check that the lateral G sensor hasn't come adrift from its mount if this was my car.

 

[st13phil]

I had unwanted ESP intervention on my smart during cornering a few times and it was extremely de-stabilising.

The active lane keeping assist function on the current W177 platform is pretty aggressive and, in the view of many, over sensitive and its intervention can easily take drivers by surprise. I can imagine scenarios in which unwanted (and unexpected) ESP intervention could easily precipitate total loss of control.

 

[Petrol Pete]

I had a similar thing on a Vauxhall Vectra years ago it was a company car and after a puncture the lease company put one brand new tyre on and it got the primitive ABS all confused but because it was not an 'active' system the ABS light just flashed now and again on the dash. A new tyre on the opposite side soon sorted it out.

What is happening to the OP's car is all together more serious.

 

[colinallcars]

Hi Again
Having received the responses to my original post I began to doubt myself and whether I was paying full attention when driving, to have potentially hit a pot hole and not seen it. Anyway, car has had little use other than running about and there have been no issues. However, today did 280 mile round trip to Poole. After 91 miles of trouble free 'roof down' driving an identical thing happened. Driving 70ish on A34 dual carriageway in clear conditions when, without me applying the brake and for no obvious reason, the brakes seemed to being applied hard automatically and car pulled fairly significantly to the right (it never does normally under braking). The Orange triangle in the centre of instrument panel came on briefly and, as it extinguished, the BAS/ESP light came on. I continued to destination trouble free. When I restarted the car the BAS/ESP had reset and no lights showed.

On the return I turned off the ESP and the orange triangle on dash was illuminated as I drove. I drove for 40 miles and the same thing happened despite ESP being off. The pull right was not as significant as I was only doing about 50. The orange triangle went out and the BAS/ESP came on and remained on for the rest of the journey.

One thing I did notice after both events on both journeys today was that footbrake did not have its usual soft and efficient feel...it felt that I was having to push harder to brake and got more feedback through the brake pedal.

Any thought on what is going wrong would be appreciated. I suspect it will be off to the Indy next week but just wanted and further ideas before hand.
Thanks

Could be the brake assist (BAS) sensing a skid? It applies the brakes pretty firmly to say the least! As to why it’s sensing a skid, check your tyre pressures as incorrect ones can confuse the system. Do you have standard tyres fitted? Changes here can also cause problems, maybe even one of the tyres being an incorrect size.

 

[Bellow]

The active lane keeping assist function on the current W177 platform is pretty aggressive and, in the view of many, over sensitive and its intervention can easily take drivers by surprise. I can imagine scenarios in which unwanted (and unexpected) ESP intervention could easily precipitate total loss of control.

It was more than a few times - it was a constant until I learned the solution (battery disconnect to reset the ECU) and had to moderate my cornering speed until then. It would have spat me off the road if I hadn't.
It's ability to save the day when there is a real slide on is something else though. 70 mph on a downhill off camber bend greasy with salt and the tail let go with no more provocation than a trailed throttle on a 72'' wheelbase car with 2/3rds rearwards weight distribution. What finished that car off was the failure of the ABS/ESP control module (a £1700 part) but without it, it was finished that day on that bend.

 

[st13phil]

It's ability to save the day when there is a real slide on is something else though.

Oh, there's no question about that. When it does the job it's supposed to do (rather than malfunctioning) I liken the MB ESP to a very large God-like hand grabbing hold of the car and guiding it back on track.

However...

An unwarranted and, by definition, unexpected intervention by malfunctioning automation can and does have catastrophic consequences, not least because the driver will tend to fight against the unexpected intervention. This is a well-understood problem in commercial aviation (B737 MAX, anybody?) because the person at the controls is a) taken by surprise at the intervention, b) they take time to assimilate what is happening, and c) in the intervening time take what they believe is corrective action that may actually make the situation worse. In the aviation world that tends to result in a smoking hole ending.

Returning to automotive automation...

Faults that could result in uncommanded directional control inputs (brake or steering intervention, etc.) should result in functionality of the intervention system being disabled and that disabling being flagged up to the driver by way of a warning. That the OP is experiencing uncommanded inputs without prior warning of a malfunction is seriously worrying.