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Does anyone know when the 3 active mounts switch from soft to hard?
I have never seen anything definitive from AMG about it. But I imagine that it is part of the overall suspension/adaption changes on a dynamic basis according to both how the car is driven and the program one has set. I don't think it is just either hard or soft but I could be wrong.
18 AMG GTC and 22 F150 Limited. Past owner 16 Maybach, 17 Brabus Smartcar, 06 Ford E150, and 22 G70
Funny you brought this up. The other day I changed the fluid on my transmission on the GTC. I had to remove a small gas strut from the bottom of the trans to get at one of the three drain plugs. This gas strut resembled the sort you would see holding up a trunk lid but this one was only about eight inches end to end. IT DID NOT HAVE any electrical hook up to change its damping rate.
Funny you brought this up. The other day I changed the fluid on my transmission on the GTC. I had to remove a small gas strut from the bottom of the trans to get at one of the three drain plugs. This gas strut resembled the sort you would see holding up a trunk lid but this one was only about eight inches end to end. IT DID NOT HAVE any electrical hook up to change its damping rate.
The adjustable mounts look like this, if your car has them. I believe in the US the active mounts are standard on the GTC, but in Canada (and I'm sure other markets), this is an option. If the analogue dash gauges are trimmed in yellow, then your car has the active mounts. If in red, it does not.
It's hard to know how the dynamic engine mounts change without trying a similar car without them on track. My only direct experience with them is when I got this attached message and it turns out one of the mounts had a short.
Agreed, this is why it would be good to know how to change their hardness. Definitely going from Comfort to Race must do it; but so many other attributes change, it’s hard to know what comes from the mounts.
I was under the impression that the mounts were only active in Race or M modes, found the following on daimler.com. It appears that the mounts may be active all the time but I'll leave it to each to make their own interpretation.
AMG DYNAMIC PLUS package available as an option for the GT S
The Mercedes-AMG GT comes as standard with drivetrain damping. A specially tuned damper reduces undesirable rolling motion of the entire drivetrain including the transaxle transmission, thus substantially improving comfort and agility.
The AMG DYNAMIC PLUS package augments dynamism and agility even more. It is available exclusively for the GT S and includes dynamic engine and transmission mounts. The engine and transmission mounts assume an important function in the case of a transaxle design: soft mounts improve comfort since they provide more effective decoupling of noise and vibration. Handling and agility benefit, however, from an overall stiffer mount set-up.
Mercedes-AMG resolves these conflicting objectives using dynamic mounts, which adjust their stiffness continuously and instantly to the respective driving conditions and handling. The special control electronics in the AMG CHASSIS CONTROLLER, ACC, provide this function. The ACC detects driving situations on the basis of CAN data, is connected to the electronic rear-axle locking differential and thus ensures optimum, balanced driving dynamics. AMG has gone a step further when implementing this technology: the engine and transmission mounts are even actuated independently of each other. The advantage: this innovative solution provides an additional substantial improvement in driving precision and lateral dynamics.
Jochen Hermann, Head of Overall Vehicle Engineering AMG: "The combination of selectively variable mounts and a transaxle drivetrain is unique. Mercedes-AMG is once again promoting leading-edge technology, thus affirming our aspirations in terms of driving performance."
A specific engine application in the DYNAMIC SELECT "RACE" drive mode and in the manual "M" transmission mode makes the GT S even more dynamic. The package also includes tauter suspension tuning thanks to raised spring and damping characteristics, more negative camber at the front axle as well as an adapted sports speed-sensitive steering. Thus the driver benefits from better performance with optimised handling. The performance steering wheel as well as yellow highlights in the instrument cluster round off the AMG DYNAMIC PLUS package.
My belief has always been that they are filled with magnetorheorogical fluid, similar to what is in the General Motors magnetic ride. The fluid is controlled by electrical current. When the computer senses it is being driven easily, the fluid flows easier. When the computer senses harder driving, it stiffens up. In the GM Magnetic ride, the computer monitors it 1000 times a second.
Does anyone know when the 3 active mounts switch from soft to hard?
Hello, I've owned my GTC for 5 yrs now - it just threw a dash error (suspension-looking icon in yellow) - dealer confirmed that it's a transaxle mount connectivity issue to wiring (one side only) - they've recommended a harness inspection; apparently the mount itself and the control unit are fine. Can I ignore and just live with the error? Concerned that if one mount is stiff (e.g. I switch to sport+ mode from comfort), and the other remains less stiff, would this create torque/tension on the transaxle housing, and more problems down the road. Dealer blames the fact that i store the car in my unheated garage for 6 months (I'm in southern Canada) and like hydro lines, the expansion/contraction of the wiring in the harness may have created a connectivity/continuity problem. Not really wanting them to get into the floor and glove box area to go fishing....
Hello, I've owned my GTC for 5 yrs now - it just threw a dash error (suspension-looking icon in yellow) - dealer confirmed that it's a transaxle mount connectivity issue to wiring (one side only) - they've recommended a harness inspection; apparently the mount itself and the control unit are fine. Can I ignore and just live with the error? Concerned that if one mount is stiff (e.g. I switch to sport+ mode from comfort), and the other remains less stiff, would this create torque/tension on the transaxle housing, and more problems down the road. Dealer blames the fact that i store the car in my unheated garage for 6 months (I'm in southern Canada) and like hydro lines, the expansion/contraction of the wiring in the harness may have created a connectivity/continuity problem. Not really wanting them to get into the floor and glove box area to go fishing....
How do you know the wiring harness in question is under the floor? It should not be a difficult job, assuming the wire is not hard to access.
Hello, I've owned my GTC for 5 yrs now - it just threw a dash error (suspension-looking icon in yellow) - dealer confirmed that it's a transaxle mount connectivity issue to wiring (one side only) - they've recommended a harness inspection; apparently the mount itself and the control unit are fine. Can I ignore and just live with the error? Concerned that if one mount is stiff (e.g. I switch to sport+ mode from comfort), and the other remains less stiff, would this create torque/tension on the transaxle housing, and more problems down the road. Dealer blames the fact that i store the car in my unheated garage for 6 months (I'm in southern Canada) and like hydro lines, the expansion/contraction of the wiring in the harness may have created a connectivity/continuity problem. Not really wanting them to get into the floor and glove box area to go fishing....
Depending on how you drive the car you may end up putting more stress on the remaining mounts and cause them to fail. If the connection to the mount is failing, then the it will just be at its softest setting at all times. Supplying a current to the mount is what stiffens it up. So if you just drive pretty normally w/o much cornering forces then you'll probably be fine, because all the other mounts remain soft as well. However, if you start driving dynamically and the other mounts start stiffening up, then the faulty one will cause an imbalance, but it's possible that the control unit will go into a failure mode and not stiffen up the others if one is failing. I don't know that, though.
The way AMG controls the mounts has changed over the years. In more recent models the mounts are mainly speed driven. They stiffen up the faster you drive. Previously they haven't really disclosed when they stiffen. It could be as soon as the car is put into the sportier modes or when it senses a more dynamic driving style.
Last edited by superswiss; 06-08-2023 at 01:27 PM.
Hello, I've owned my GTC for 5 yrs now - it just threw a dash error (suspension-looking icon in yellow) - dealer confirmed that it's a transaxle mount connectivity issue to wiring (one side only) - they've recommended a harness inspection; apparently the mount itself and the control unit are fine. Can I ignore and just live with the error? Concerned that if one mount is stiff (e.g. I switch to sport+ mode from comfort), and the other remains less stiff, would this create torque/tension on the transaxle housing, and more problems down the road. Dealer blames the fact that i store the car in my unheated garage for 6 months (I'm in southern Canada) and like hydro lines, the expansion/contraction of the wiring in the harness may have created a connectivity/continuity problem. Not really wanting them to get into the floor and glove box area to go fishing....
Depending on how you drive the car you may end up putting more stress on the remaining mounts and cause them to fail. If the connection to the mount is failing, then the it will just be at it softest setting at all times. Supplying a current to the mount is what stiffens it up. So if you just drive pretty normally w/o much cornering forces then you'll probably be fine, because all the other mounts remains soft as well. However, if you start driving dynamically and the other mounts start stiffening up, then the faulty one will cause an imbalance.
The way AMG controls the mounts has changed over the years. In more recent models the mounts are mainly speed driven. They stiffen up the faster you drive. Previously they haven't really disclosed when they stiffen. It could be as soon as the car is put into the sportier modes or when it measures higher lateral acceleration.
How do you know the wiring harness in question is under the floor? It should not be a difficult job, assuming the wire is not hard to access.
The service tech mentioned that this is where it is. Also, they’d have to dismantle some of the dash/glovebox area and they’re really reluctant to do so (never the same fit compared to when it came from the factory).
I had the same warning light as the person above on my 2018 GTC (Canadian spec) during the final heats at Willow Springs in April. Car drove fine, managed to do another full day at Thunder Hill and drove back to Vancouver (and then a few weeks more) before the dealer got my car in for service.
Mounts replaced under warranty, has been fine since!
04-19-2020, 10:58 AM
active transaxle mount error
