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Looks like my AMG Active Ride Control broke today. I was almost home after an 800+ mile road trip on mostly 2 lane roads. (with lots of fun curves) I admit to pushing the suspension frequently and saw 8 & 9 degree lean readings a few times. It’s difficult glancing at the dash when pushing the limits so I really don’t know if there were higher readings.
This is the warning that popped up on my normally flat cornering GLE 53 as it started leaning a lot in curves. I don’t recall anyone else reporting anything similar.
Looks like my AMG Active Ride Control broke today. I was almost home after an 800+ mile road trip on mostly 2 lane roads. (with lots of fun curves) I admit to pushing the suspension frequently and saw 8 & 9 degree lean readings a few times. It’s difficult glancing at the dash when pushing the limits so I really don’t know if there were higher readings.
This is the warning that popped up on my normally flat cornering GLE 53 as it started leaning a lot in curves. I don’t recall anyone else reporting anything similar.
Hmm. It will be interesting to see if it goes away after an overnight sleep. If you take it to the dealer please post the codes/findings. Do you have a code reader?
It could be a simple electrical component failure. There is no noise. The sway bars seem to have no resistance normally until activated and that’s the way they feel now. I don’t read codes and emailed the picture and explanation to the Shop Foreman and my Service Advisor a couple of hours before closing time, but it’s Friday! I’m hoping I can skip one trip to “observe the issue” to the Dealer, maybe just drop by to let them read the code while waiting.
The rolls bars are electrically controlled with a motor versus the more traditional and simple physical bar. It could be something as simple as a bad sensor or the entire motor went kaput.
Well….after sitting overnight the active sway bar is working again. It’s possible that the front electric motor overheated since I had just gone through about 30 miles of curves on a hot afternoon. I never could determine if the rear was still working…I thought not, but the front was rolling so much it was hard to tell. I’ll post what I learn from the error code.
It could be a simple electrical component failure. There is no noise. The sway bars seem to have no resistance normally until activated and that’s the way they feel now. I don’t read codes and emailed the picture and explanation to the Shop Foreman and my Service Advisor a couple of hours before closing time, but it’s Friday! I’m hoping I can skip one trip to “observe the issue” to the Dealer, maybe just drop by to let them read the code while waiting.
I got a similar message after going off track and hitting a prairie dog hole sideways at speed.
It turned out that I had moved the alignment at the left rear, so it moved as I drove, after the incident.
The ride was like I had no suspension at all - Rock hard.
Had it towed to the dealer.
Realigned, replaced an alignment bolt or two, just in case they stretched, and I'm back on the road.
It wasn't the active suspension.
As an aside, my interpretation of that display in your left cluster, is that it's not related to G-Force, but instead it's related to the center of the Earth. Otherwise known as the camber of the road or super-elevation of the corner.
I had both the g-force display and the level display going, and they seemed unrelated.
Well, it’s good to hear it’s working again. Hopefully it’s nothing major and an easy fix. This is one of those features that is certainly cutting edge but maybe it’s too smart for its own good, where a simple stiff metal bar would have sufficed.
Well, it’s good to hear it’s working again. Hopefully it’s nothing major and an easy fix. This is one of those features that is certainly cutting edge but maybe it’s too smart for its own good, where a simple stiff metal bar would have sufficed.
It was a bolt. And a crash. Not very cutting edge.
ARC is also much more elegant solution than the competition, fewer moving parts, and more direct control.
Also an improvement in simplicity, compared to previous Mercedes implementations.
As an aside, my interpretation of that display in your left cluster, is that it's not related to G-Force, but instead it's related to the center of the Earth. Otherwise known as the camber of the road or super-elevation of the corner.
I had both the g-force display and the level display going, and they seemed unrelated.
I hope I didn’t say G force anywhere. My interpretation was that it’s measuring the amount of adjustment in the roll bar in degrees of body roll it’s correcting. The curves aren’t banked around here but flat or at most 1 degree according to that same display. They try to crown the center of the roads to drain away on each side. The last stretch is fairly flat but with twisty curves following a river. There is no way that any were banked anywhere close to the readings on the display. It’s easy to compare by going slow around it one time and then speeding up to see a higher reading the next time.
The rolls bars are electrically controlled with a motor versus the more traditional and simple physical bar. It could be something as simple as a bad sensor or the entire motor went kaput.
From that second link in my post, it seems to say that there are two actuating motors at each end of the car, not one motor with two planetary gears.
Plus, the active diagram on my center display shows two separate activators, each controlling their own sway bar. I have also seen the claims of 800 foot pounds aimed at each corner.
So I still wonder how many step motors there are at each end, and what the car uses to activate them. I suspect all the usual body roll and acceleration sensors, augmented by a velocity sensor that determines the speed of suspension movements.
From that second link in my post, it seems to say that there are two actuating motors at each end of the car, not one motor with two planetary gears.
Plus, the active diagram on my center display shows two separate activators, each controlling their own sway bar. I have also seen the claims of 800 foot pounds aimed at each corner.
So I still wonder how many step motors there are at each end, and what the car uses to activate them. I suspect all the usual body roll and acceleration sensors, augmented by a velocity sensor that determines the speed of suspension movements.
In the second link above the phrase “each axle” means each pair of wheels. There is one active roll actuator per axle, in other words one in the front suspension and one in the rear suspension. Not two actuators in any one suspension. The system is a stabilizer bar cut into two pieces, each piece joined in the middle by an actuator.
Wheel acceleration can be calculated as the second derivative of wheel position over time, in reference to a comment from the second link above.
In addition to camera inputs, the standard vehicle dynamic control system inputs are used, same as for all cars with vehicle dynamic control systems such as ESP. This means substantially all passenger cars.
Primary inputs:
steering wheel angle
gas pedal position
Primary measurements:
vehicle speed
yaw rate
lateral acceleration
roll angle and roll velocity
transmission gear status
…plus more
From these the active stabilizer bar software decides what actuation, if any, should be done by the hydraulic (Active Curve) or 48V (AMG Ride Control) actuator.
From that second link in my post, it seems to say that there are two actuating motors at each end of the car, not one motor with two planetary gears.
Plus, the active diagram on my center display shows two separate activators, each controlling their own sway bar. I have also seen the claims of 800 foot pounds aimed at each corner.
So I still wonder how many step motors there are at each end, and what the car uses to activate them. I suspect all the usual body roll and acceleration sensors, augmented by a velocity sensor that determines the speed of suspension movements.
Wouldn’t there would be two motors, one at each end-front and rear? That’s the way the skeleton cut away by Audi displays it. One motor in the center of the roll bar twisting up on one side and down on the other side. Much more effective than just trying to lift one side. I’m convinced that Mercedes and VAG vehicles use a similar system.
Wouldn’t there would be two motors, one at each end-front and rear? That’s the way the skeleton cut away by Audi displays it. One motor in the center of the roll bar twisting up on one side and down on the other side. Much more effective than just trying to lift one side. I’m convinced that Mercedes and VAG vehicles use a similar system.
Yes.
One actuator per axle. Two total actuators per vehicle, if the active roll system is installed on both axles.
I hope I didn’t say G force anywhere. My interpretation was that it’s measuring the amount of adjustment in the roll bar in degrees of body roll it’s correcting. The curves aren’t banked around here but flat or at most 1 degree according to that same display. They try to crown the center of the roads to drain away on each side. The last stretch is fairly flat but with twisty curves following a river. There is no way that any were banked anywhere close to the readings on the display. It’s easy to compare by going slow around it one time and then speeding up to see a higher reading the next time.
The display on the left is showing degrees of body roll and % grade.
The display on the left is showing degrees of body roll and % grade.
Maybe… a degree or two might be hard to notice but the car stays very flat and in no way it has 8-9 degrees of actual roll when I see that reading. Might be just inaccurate when the Active Body Control is compensating but there is a correlation to higher speed in corners even though the chassis stays flat…play on words for Chassis.😬
Maybe… a degree or two might be hard to notice but the car stays very flat and in no way it has 8-9 degrees of actual roll when I see that reading. Might be just inaccurate when the Active Body Control is compensating but there is a correlation to higher speed in corners even though the chassis stays flat…play on words for Chassis.😬
I still believe the degree display is in a relation to the Earth.
I'm not sure I've ever seen a real paved Road that doesn't have super-elevation in corners, and 7% on a 50mph corner is about right. On some of those tight freeway flyovers, I wouldn't be surprised at double that
I agree, there's no way you'd see that much lean on an ARC car. The tires would let go first.
I still believe the degree display is in a relation to the Earth.
I'm not sure I've ever seen a real paved Road that doesn't have super-elevation in corners, and 7% on a 50mph corner is about right. On some of those tight freeway flyovers, I wouldn't be surprised at double that
I agree, there's no way you'd see that much lean on an ARC car. The tires would let go first.
I agree the display is normally measuring the slope of the ground and might be designed more for off road use. Mine reacts different at speed.
Try a curve on flat ground, 2 lane road and drive slowly around it watching the degree reading. Then repeat on the same curve at a higher speed. See if your reading doesn’t increase the second time. Inside lanes tend to be slightly banked, outside lanes are not on the two I tested. A mountain road following a river with a 30/35 mph limit is a good example. On these, where ice is an issue, they tend to crown the center for drainage in our area.
I agree the display is normally measuring the slope of the ground and might be designed more for off road use. Mine reacts different at speed.
Try a curve on flat ground, 2 lane road and drive slowly around it watching the degree reading. Then repeat on the same curve at a higher speed. See if your reading doesn’t increase the second time. Inside lanes tend to be slightly banked, outside lanes are not on the two I tested. A mountain road following a river with a 30/35 mph limit is a good example. On these, where ice is an issue, they tend to crown the center for drainage in our area.
I've tried that before just to verify my thoughts on the displays, but I'll do it again. Good reason to carve some corners.
The display on the left is showing degrees of body roll and % grade.
I'm taking Ron's challenge to go verify that body roll statement. I think the lateral and longitudinal both refer to the Earth and grade angle. I'll report back later today.
I'm taking Ron's challenge to go verify that body roll statement. I think the lateral and longitudinal both refer to the Earth and grade angle. I'll report back later today.
Assignment completed
I found a nearby corner that I could drive at different speeds and photograph my instrument cluster displays. I set left display for inclination (if that's what it's really showing) and the right one for G-Force. Corner taken at 15 mph, near 0 g's on right display. Same corner at 55, 0.3 g's.
Both taken in comfort mode.
I'd say the left one is an inclinometer. And, as Ron said, it's probably more for off-road use.
As far as the banking in a corner, which I call super-elevation, the next corner is a 40 mile an hour corner, and I stopped right in the middle of it and it measured 7° banking. Had to scoot to get out of the oncoming traffic, so no photo there.
I'm taking Ron's challenge to go verify that body roll statement. I think the lateral and longitudinal both refer to the Earth and grade angle. I'll report back later today.
‘Mike you got me second guessing myself so I took the challenge today. Sunday there were lots of empty parking lots. Turning in a circle to the right under acceleration I saw +7 degrees without much effort. Reverse direction and I got -7 degrees…Much the same result making a turn at an intersection under power. +4 right & same intersection -4 left
‘Mike you got me second guessing myself so I took the challenge today. Sunday there were lots of empty parking lots. Turning in a circle to the right under acceleration I saw +7 degrees without much effort. Reverse direction and I got -7 degrees…Much the same result making a turn at an intersection under power. +4 right & same intersection -4 left
I agree with mikapen. Note the left gauge goes to 35 degrees. No way you are going to get 35 degrees body roll; you'd be on your door handles almost! And there is no real reason to display body roll angles. These are for off road showing slope in direction of travel and cross slope, both of which are important in that situation. Could be Ron's observations are just the sensors being affected by the hard cornering. My manual (p. 255) calls the display "angle incline and approach / departure," which is not totally clear but has nothing to do with body roll.
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