F30POST
F30POST
2012-2015 BMW 3-Series and 4-Series Forum
BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read
BMW 3-Series and 4-Series Forum (F30 / F32) | F30POST > Technical Forums > Suspension | Chassis | Brakes > Explanation of How M Adaptive Suspension Works
Extreme Powerhouse
Post Reply
 
Thread Tools Search this Thread
      02-06-2014, 01:31 PM   #67
DVC
Diligentia Vis Celeritas
DVC's Avatar
United_States
558
Rep
1,477
Posts

Drives: 335i
Join Date: Apr 2013
Location: Northern NJ

iTrader: (1)

Garage List
Quote:
Originally Posted by BMWintoxication View Post


ZHP, DTC, EDC, and now A-S-S. woohooo!! LOL
Oh - right... that acronym is already taken! lol


Quote:
Originally Posted by Jamesons Viggen View Post
I have done spring installs at EuroTire and Redline Speed Worx did my F30.
RS Worx looks to be pretty close-by - I'll check 'em out... Thanks JV!
__________________
Ahead of the curve for specF30
Appreciate 0
      02-06-2014, 03:59 PM   #68
Jamesons Viggen
Brigadier General
United_States
193
Rep
3,780
Posts

Drives: '98 M Roadster stg 2+ S/C
Join Date: Jul 2012
Location: Rochester Hills MI

iTrader: (3)

Quote:
Originally Posted by DVC View Post
Oh - right... that acronym is already taken! lol




RS Worx looks to be pretty close-by - I'll check 'em out... Thanks JV!
They did my install for under $400, but I am yet to have an alignment though its on my to-do list after winter.
__________________

'98 Dinan/RMS stage 2+(VAC cams, CES Cutring etc)
'15 Buick Regal "T"(wife)
'06 Saab 9-5 Combi 5mt (full suspension, LSD, clipped turbo etc)
Appreciate 0
      02-06-2014, 10:08 PM   #69
Racer20
Major
United_States
1030
Rep
1,190
Posts

Drives: F80 M3, 228i THP, E46 ZHP
Join Date: May 2009
Location: Ann Arbor, MI

iTrader: (0)

Quote:
Originally Posted by antastik View Post
Hey Racer20, very interesting subject.
By the way, I have the adaptive suspension system on the BMW F20 and I was wondering whether it is the same as F30. More in general, as far as you know, is this system of the kind that has a dedicated ECU?
The reason for asking is that some suppliers, including Tenneco, use the term adaptive also for simplified suspension systems that have a limited electronic onboard the damper and no dedicated ECU.
Thank you very much
I believe it has a separate ECU, but the F20 isn't out in my market, so I'm not really that familiar with it.
Appreciate 0
      02-11-2014, 03:13 PM   #70
DVC
Diligentia Vis Celeritas
DVC's Avatar
United_States
558
Rep
1,477
Posts

Drives: 335i
Join Date: Apr 2013
Location: Northern NJ

iTrader: (1)

Garage List
Quote:
Originally Posted by Racer20 View Post
I believe it has a separate ECU, but the F20 isn't out in my market, so I'm not really that familiar with it.
I just ordered some Ground Control camber plates for my F30, and had a good chat with the guy who designed them (Jay) about suspension in general, and the EDC dampers on the F30 specifically. Based on his testing with various BMW EDC damper systems, it was his opinion that it would be crazy to swap them out for aftermarket dampers - they're that good. Dinan of course says the same thing, but I always took that with a grain of salt since they sell Shockware to work with the EDC dampers... But being that Ground Control sells aftermarket dampers, it caught my attention to hear this from them.

In the stock calibration (and with the stock sport springs) the ride allows for a bit more body roll than most of us like, but with better springs (and most likely even more so with re-mapped damping curves via Shockware), I'm hoping these dampers will really shine.
__________________
Ahead of the curve for specF30
Appreciate 0
      02-11-2014, 07:30 PM   #71
stevehecht
Captain
United_States
121
Rep
704
Posts

Drives: 2014 328d
Join Date: Aug 2013
Location: Rio Rancho, NM

iTrader: (0)

Garage List
Quote:
Originally Posted by DVC View Post
I just ordered some Ground Control camber plates for my F30, and had a good chat with the guy who designed them (Jay) about suspension in general, and the EDC dampers on the F30 specifically. Based on his testing with various BMW EDC damper systems, it was his opinion that it would be crazy to swap them out for aftermarket dampers - they're that good. Dinan of course says the same thing, but I always took that with a grain of salt since they sell Shockware to work with the EDC dampers... But being that Ground Control sells aftermarket dampers, it caught my attention to hear this from them.

In the stock calibration (and with the stock sport springs) the ride allows for a bit more body roll than most of us like, but with better springs (and most likely even more so with re-mapped damping curves via Shockware), I'm hoping these dampers will really shine.
Good information, thanks. There's no definite ETA yet on the Shockware, is there? Last I heard in the fall it was going to be the second half of 2014.
__________________
2014 328d SportLine
Appreciate 0
      06-19-2015, 05:31 PM   #72
Racer20
Major
United_States
1030
Rep
1,190
Posts

Drives: F80 M3, 228i THP, E46 ZHP
Join Date: May 2009
Location: Ann Arbor, MI

iTrader: (0)

Quote:
Originally Posted by CanAutM3 View Post
I fully agree on the principle that less weight transfer means more total grip, but I am a bit puzzled by the above statement.

I also understand that there is some weight transfer due to roll, dive and squat due to the Cg moving about the roll/dive/squat centers. But I have always understood that this later weight transfer is relatively minimal to the point of being negligible compared to the weight transfer caused by acceleration/traction forces. The weight transfer is what causes the roll, not the other way around (except for the small aforementioned amount).

My understanding is that, in transient mode, while the suspension is taking a set, a stiffer damper will resist (slow down) the roll process but the weight transfer still occurs. If the acceleration/traction forces are sustained long enough, the suspension eventually takes a set and at that point the damper stiffness is irrelevant to how much the car rolls and the weight transfer is still mostly dependent on the traction/acceleration forces. Same logic applies to longitudinal acceleration/traction and dive/squat. If you mean stiffer suspension through stiffer springs, yes I agree, there will be less roll, but not less weight transfer. But spring rates are not altered by variable dampers.

Thoughts?

BTW, great write-up. It was a very interesting read .
I know this is long dead, but I just realized that I never responded to the good points and questions you bring up.

Yes, the statement "stiffer springs resist weight transfer" is not correct. It's actually the exact opposite. I'm not sure what I was thinking when I wrote it, other than that it was not really the central point of my post and I kind of just put that in there as a segway without any real thought (Oops!). For that post, I should have said was that stiffer suspension has some benefits to laptimes and handling and left it at that. Anway, Here's a better go at explaining stiffness vs. weight transfer.

Quote:
a stiffer damper will resist (slow down) the roll process but the weight transfer still occurs. If the acceleration/traction forces are sustained long enough, the suspension eventually takes a set and at that point the damper stiffness is irrelevant
This is spot on.

You are also correct that, in steady state cornering, the total amount of lateral weight transfer is independent of suspension stiffness. But, the front to rear distribution of the weight transfer does depend on suspension stiffness. (In this situation, I'm basically reffering to roll stiffness via springs and bars.)

Key point:
Quote:
Remember, a pair of tires (fronts or rears) will have the highest total grip capacity when the load on them is equal. Therefore, anytime you transfer weight from one side to the other in a corner, you diminish your total grip.
Now, imagine a car with 50/50 weight distribution and equal front and rear roll stiffness. In a corner, that car transfers 1000lbs from the inside to the outside corner. That transfer happens equally in the front and in the rear, and both the front and rear tires lose the same amount of grip due to the key point above. Here's a crappy visualization of the corner weights for this scenario.

Sitting still:


1000lbs 1000lbs


1000lbs 1000lbs

During a left turn:


500lbs 1500lbs


500lbs 1500lbs

You've transferred 500lbs in the front, and 500lbs in the rear, and lost the same amount of grip in the front as you have at the rear. The balance of the car is neutral.

If you then increase the REAR roll stiffness of this same car, you will still have the same 1000lbs total weight transfer, but the front to rear distribution will not be equal any more. You might have something like this:

Left turn with stiffer rear springs:

700lbs 1300lbs


300lbs 1700lbs <-- stiffer springs = more transfer in the rear

Now, the front tires have 400lbs difference left to right, and the rear tires have 1400lbs difference left to right. You have now lost MORE grip in the rear than in the front, and made the car oversteer. If you were to increase the front stiffness instead, you would now have an understeering car.

This is basically the mechanism by which you tune for oversteer/understeer with springs and bars.

Sorry it took me 2 years to get back to you!
__________________
2015 M3, 2005 330i ZHP, 2015 228i 6MT Track Handling Pack, 2007 M Coupe (Sold)

Last edited by Racer20; 06-20-2015 at 11:02 AM..
Appreciate 1
      06-20-2015, 09:24 AM   #73
CanAutM3
General
CanAutM3's Avatar
Canada
21105
Rep
20,741
Posts

Drives: 2021 911 turbo
Join Date: Jan 2012
Location: Montreal

iTrader: (1)

Garage List
Quote:
Originally Posted by Racer20 View Post
I know this is long dead, but I just realized that I never responded to the good points and questions you bring up.

Yes, the statement "stiffer springs resist weight transfer" is not correct. It's actually the exact opposite. I'm not sure what I was thinking when I wrote it, other than that it was not really the central point of my post and I kind of just put that in there as a segway without any real thought (Oops!). For that post, I should have said was that stiffer suspension has some benefits to laptimes and handling and left it at that. Anway, Here's a better go at explaining stiffness vs. weight transfer.



This is spot on.

You are also correct that, in steady state cornering, the total amount of lateral weight transfer is independent of suspension stiffness. But, the front to rear distribution of the weight transfer does depend on suspension stiffness. (In this situation, I'm basically reffering to roll stiffness via springs and bars.)

Key point:

Remember, a pair of tires (fronts or rears) will have the highest total grip capacity when the load on them is equal. Therefore, anytime you transfer weight from one side to the other in a corner, you diminish your total grip.

Now, imagine a car with 50/50 weight distribution and equal front and rear roll stiffness. In a corner, that car transfers 1000lbs from the inside to the outside corner. That transfer happens equally in the front and in the rear, and both the front and rear tires lose the same amount of grip due to the key point above. Here's a crappy visualization of the corner weights for this scenario.

Sitting still:


1000lbs 1000lbs


1000lbs 1000lbs

During a left turn:


500lbs 1500lbs


500lbs 1500lbs

You've transferred 500lbs in the front, and 500lbs in the rear, and lost the same amount of grip in the front as you have at the rear. The balance of the car is neutral.

If you then increase the REAR roll stiffness of this same car, you will still have the same 1000lbs total weight transfer, but the front to rear distribution will not be equal any more. You might have something like this:

Left turn with stiffer rear springs:

800lbs 1200lbs


300lbs 1700lbs <-- stiffer springs = more transfer in the rear

Now, the front tires have 400lbs difference left to right, and the rear tires have 1400lbs difference left to right. You have now lost MORE grip in the rear than in the front, and made the car oversteer. If you were to increase the front stiffness instead, you would now have an understeering car.

This is basically the mechanism by which you tune for oversteer/understeer with springs and bars.

Sorry it took me 2 years to get back to you!
Thank you for getting back to me. I always appreciate reading your insights. Very nice and simple illustration of how playing with the front to rear spring rates ratio changes the weight transfer at each corner and alters the handling dynamics. It just shows how complex it is to properly tune the handling of a car. Aftermarket lowering springs that are just thrown on the market without extensive development can easily make the handling worse.

If we agree to slightly modify your above example to something like this, we are fully on the same page
Left turn with stiffer rear springs:

700lbs 1300lbs

300lbs 1700lbs <-- stiffer springs = more transfer in the rear
PS: Just nitpicking to nag you
__________________
Porsche 911 turbo 2021 992 GT Silver

Previous cars: M4cs 2019 F82 Limerock Grey / M4 2015 F82 Silverstone / M3 2008 E92 Silverstone / M3 2002 E46 Carbon Black

Last edited by CanAutM3; 06-20-2015 at 09:32 AM..
Appreciate 0
      06-20-2015, 11:00 AM   #74
Racer20
Major
United_States
1030
Rep
1,190
Posts

Drives: F80 M3, 228i THP, E46 ZHP
Join Date: May 2009
Location: Ann Arbor, MI

iTrader: (0)

Quote:
Originally Posted by CanAutM3 View Post
PS: Just nitpicking to nag you
Nah, thanks for keeping me honest.
__________________
2015 M3, 2005 330i ZHP, 2015 228i 6MT Track Handling Pack, 2007 M Coupe (Sold)
Appreciate 0
      01-31-2016, 09:24 PM   #75
DJ Rocc
Major
DJ Rocc's Avatar
Jamaica
199
Rep
1,114
Posts

Drives: BMW 428i Gran Coupe (2015)
Join Date: May 2014
Location: Kingston, Jamaica

iTrader: (0)

Quote:
Originally Posted by Racer20 View Post
Nah, thanks for keeping me honest.
Hey Racer20! Great insight into the M Adaptive Suspension!!

I have. 2015 428i with M Adaptive Suspension, how would you know if it was performing to specs, or performing at all? Is there a way of testing this?

I know when I move from Comfort to Sport Mode, the Springs do get tighter, and the car definitely is more stiff and responsive.

But just wondering how smooth of a ride it is supposed to give?

Also, noticed that I have to keep my tires (runflats) inflated to their highest spec (5 passengers and luggage PSI) in order for me to get the most compliant ride. Otherwise I get a really "bouncy" type of ride.
__________________
My Ride! : 2015 428i GC (F36) - MSport, Alpine, Black Leather, MBrakes, Adaptive, Sport Seats, Hex. Alum w/Piano, HK Sound, 400m's, Comfort Acc. When I’m not Driving: https://youtube.com/shorts/ViKD_Hj5htE?feature=share
Appreciate 0
      01-31-2016, 09:55 PM   #76
sygazelle
Brigadier General
11114
Rep
3,404
Posts

Drives: 2014 328i M-Sport, 2019 X5 40i
Join Date: Sep 2010
Location: San Francisco

iTrader: (0)

Quote:
Originally Posted by DJ Rocc View Post
Hey Racer20! Great insight into the M Adaptive Suspension!!

I have. 2015 428i with M Adaptive Suspension, how would you know if it was performing to specs, or performing at all? Is there a way of testing this?

I know when I move from Comfort to Sport Mode, the Springs do get tighter, and the car definitely is more stiff and responsive.

But just wondering how smooth of a ride it is supposed to give?

Also, noticed that I have to keep my tires (runflats) inflated to their highest spec (5 passengers and luggage PSI) in order for me to get the most compliant ride. Otherwise I get a really "bouncy" type of ride.

If you are getting a bouncy ride, think about getting Dinan Shockware. I upgraded my 2014 328i with Adaptive Suspension last year and I couldn't be happier. Before Dinan Shockware, my Comfort mode was horrible. It was bouncy or porpoise-like. Sport mode was less so, but still annoying. I was always reaching for the mode switch the moment I got into the car to get the heck out of the awful Comfort mode. THEN, I got the Dinan Shockware upgrade. It transformed the car. No more bouncy. No more porpoise-like ride. Comfort feels like Sport mode should. Sport mode is even tighter. Comfort is now so good I only change to Sport when I am feeling extra sporty

Read about Dinan Shockware and see if its some you would consider. Note that it is not springs or hardware; it's it a software update.

Good luck!
Appreciate 0
      02-05-2016, 05:36 AM   #77
DJ Rocc
Major
DJ Rocc's Avatar
Jamaica
199
Rep
1,114
Posts

Drives: BMW 428i Gran Coupe (2015)
Join Date: May 2014
Location: Kingston, Jamaica

iTrader: (0)

Quote:
Originally Posted by sygazelle View Post
If you are getting a bouncy ride, think about getting Dinan Shockware. I upgraded my 2014 328i with Adaptive Suspension last year and I couldn't be happier. Before Dinan Shockware, my Comfort mode was horrible. It was bouncy or porpoise-like. Sport mode was less so, but still annoying. I was always reaching for the mode switch the moment I got into the car to get the heck out of the awful Comfort mode. THEN, I got the Dinan Shockware upgrade. It transformed the car. No more bouncy. No more porpoise-like ride. Comfort feels like Sport mode should. Sport mode is even tighter. Comfort is now so good I only change to Sport when I am feeling extra sporty

Read about Dinan Shockware and see if its some you would consider. Note that it is not springs or hardware; it's it a software update.

Good luck!
Thank You Sygazelle for your input! I will certainly tale a look at the Dinan Shockware.
__________________
My Ride! : 2015 428i GC (F36) - MSport, Alpine, Black Leather, MBrakes, Adaptive, Sport Seats, Hex. Alum w/Piano, HK Sound, 400m's, Comfort Acc. When I’m not Driving: https://youtube.com/shorts/ViKD_Hj5htE?feature=share
Appreciate 0
      02-15-2016, 12:07 PM   #78
Musashi
Colonel
136
Rep
357
Posts

Drives: BMW 335i XDrive Laguna Seca
Join Date: May 2013
Location: Canada

iTrader: (0)

new 340i suspension VS F30 Adaptive

Quote:
Originally Posted by Racer20 View Post
Nah, thanks for keeping me honest.
Hello Racer,

Am seeking some answers as to the improvements BMW made to the F30 suspension- in particular the front- and how does it compare to the fully equipped F30 with Adaptive M? Although I have experiences occasional minor understeer and maybe even roll, is the difference significant enough to
  • A- trade in the 2014 335i xDrive M Performance (last thing I would want to do) or
  • B- just go and get sway bars installed to increase overall stiffness?
Should you be able to elaborate on the differences, it would be great. Quite a few of us do not know the difference between. My 335i xDrive always felt much better than the base F30 sedan. however, the 340i makes me wonder.


regards

m
Appreciate 0
      02-16-2016, 04:02 AM   #79
boosted43
Captain
boosted43's Avatar
United_States
169
Rep
821
Posts

Drives: 2017 C43 AMG
Join Date: Apr 2011
Location: NOVA

iTrader: (1)

Garage List
2015 BMW 335i  [0.00]
I want to add in something as to the comfort level of the suspensions. I had a 2013 F30 335i Sport Line, and recently sold it and Purchased a 2015 335i with the Adaptive M Suspension.

My 2013 had 18" OEM Wheels and Stock Pirelli P7 Run Flats
My 2015 has 19" OEM Wheels and Stock Bridgestone Run Flats.

I have to say that the difference in the comfort of the ride is definitely noticeable and much improved with the M Adaptive Suspension. I don't feel like my stomach is going to come out of my mouth everytime I hit a pothole, which is how I felt on my 2013 with the M Sport Suspension (Passive)

I may look into getting the Dinan Shockware for it. Are there any other companies that "Tune" the M Adaptive Suspension? I'm assuming the tune is only software related and nothing changes as far as the hardware goes?
__________________
2014 X5 xDrive50i Mineral White | DinanTronics Stage 1 | Vossen HC3
Appreciate 0
      02-16-2016, 09:37 AM   #80
Musashi
Colonel
136
Rep
357
Posts

Drives: BMW 335i XDrive Laguna Seca
Join Date: May 2013
Location: Canada

iTrader: (0)

Dinan shockware had some v good reviews.

http://f30.bimmerpost.com/forums/sho...=974367&page=2
Appreciate 0
      08-21-2022, 03:49 PM   #81
F15er
New Member
United Kingdom
5
Rep
17
Posts

Drives: BMW X5 30d MSport
Join Date: Jul 2021
Location: United Kingdom

iTrader: (0)

Racer20

I know this is an old thread but im a bit desperate for a solution so if by an off chance someone can give me bit of an advice would be grateful.

I have F15 with Adaptive Chassis around 8 months ago my shocks gone stiff out of blue, used to drive very smoothly.

I replaced all accelerometers, ICM and VDC units, ride height calibration, edc, icm start up, steering angle calibration, software updates, flashed control units back on but no luck. (flashing ICM helped but lasted a day or 2)

It has no warning lights, no fault codes and been to 3 different garages one main dealer and 2 specialists.

One of the thinks car is normal as its an Msport but the car used to be really comfortable, and ride used to be really smooth.

Its now crashy and some days unbearable and occasionally it will sort it self out for a short period but this is now very rare and might last half a mile or 10 miles.

Something throwing the data this uses to tell shocks to stiffen up but what is it i cant find.
a
Any advice small or big would be appreciated
Appreciate 0
      08-22-2022, 05:31 AM   #82
Racer20
Major
United_States
1030
Rep
1,190
Posts

Drives: F80 M3, 228i THP, E46 ZHP
Join Date: May 2009
Location: Ann Arbor, MI

iTrader: (0)

What car do you have?
__________________
2015 M3, 2005 330i ZHP, 2015 228i 6MT Track Handling Pack, 2007 M Coupe (Sold)
Appreciate 0
      08-22-2022, 01:26 PM   #83
F15er
New Member
United Kingdom
5
Rep
17
Posts

Drives: BMW X5 30d MSport
Join Date: Jul 2021
Location: United Kingdom

iTrader: (0)

Quote:
Originally Posted by Racer20 View Post
What car do you have?

Its 2016 X5, on another forum someone had same problem, they still had the problem after changing all 4 shocks but then he replied saying the problem was the shock and replacing the faulty one resolved the issue.

I measured all the valves when the car is turned off and they all read 2 to 2,2 ohms i cannot remember where i read but supposedly thats what they should read.

Is there anyway to diagnose the shocks?
Appreciate 0
      08-23-2022, 01:16 AM   #84
casualDIYer
Major
428
Rep
1,359
Posts

Drives: 340i xDrive M Sport
Join Date: Nov 2008
Location: Toronto

iTrader: (0)

Quote:
Originally Posted by F15er View Post
Racer20

I know this is an old thread but im a bit desperate for a solution so if by an off chance someone can give me bit of an advice would be grateful.

I have F15 with Adaptive Chassis around 8 months ago my shocks gone stiff out of blue, used to drive very smoothly.

I replaced all accelerometers, ICM and VDC units, ride height calibration, edc, icm start up, steering angle calibration, software updates, flashed control units back on but no luck. (flashing ICM helped but lasted a day or 2)

It has no warning lights, no fault codes and been to 3 different garages one main dealer and 2 specialists.

One of the thinks car is normal as its an Msport but the car used to be really comfortable, and ride used to be really smooth.

Its now crashy and some days unbearable and occasionally it will sort it self out for a short period but this is now very rare and might last half a mile or 10 miles.

Something throwing the data this uses to tell shocks to stiffen up but what is it i cant find.
a
Any advice small or big would be appreciated
Wow, that is a lot of gear to swap out. It seems you are one module or sensor away from a fix. If all dampers have gone into stiff mode, either a sensor is continuing to send faulty data or the sensor is sending nothing and the car is defaulting to stiff.

You mentioned the ride height sensors have been re-calibrated. Front and rear? Testing them isn't that hard in that you can park the car on a hill with the engine and headlights on. The headlights should point in the forward direction of the vehicle.

Another approach is to disconnect all sensors and dampers (the car will throw multiple codes). Attach one damper, test, then attach a sensor, test. The idea here is you are testing not only the sensor but whether there is a short to any part of the system causing it to go haywire.

The next step is to check the wiring. To do this properly though, an oscilloscope would be a fantastic tool to help. Unfortunately, such tools are not cheap. Seek out an automotive electronics expert who can sniff the CAN bus for random garbage rather than a regular signal expected. Most mechanics, including the dealer, often do not have the experience or tools to properly do such diagnosis so it's not a surprise to hear the shops you visited missed it. You may have to seek out a specialist.

Another possibility is rusted or broken pin on a connector. You'll need to check all related modules and each connector to it, including the connectors to each damper. Rusted pins will generate inconsistent results and broken pins will shutdown parts of a system. Generally in vehicles with a sun roof (like the X5) there will be a drain that passes from top to bottom for the water to exit. If the drain pipe cracks, water or high levels of condensation end up in electronically sensitive areas. In general, when you check any module, pull out it's connectors and look for rust or broken pins. BMW sells connector pin repair kits for a reason. It's not a shock to see a dead pin, at least on a BMW.

Good luck.
__________________
340i xDrive (F30), 228i (F22), 320 (F30), 325i (E46)
Appreciate 1
F15er4.50
      08-23-2022, 01:18 PM   #85
F15er
New Member
United Kingdom
5
Rep
17
Posts

Drives: BMW X5 30d MSport
Join Date: Jul 2021
Location: United Kingdom

iTrader: (0)

Quote:
Originally Posted by casualDIYer View Post
Wow, that is a lot of gear to swap out. It seems you are one module or sensor away from a fix. If all dampers have gone into stiff mode, either a sensor is continuing to send faulty data or the sensor is sending nothing and the car is defaulting to stiff.

You mentioned the ride height sensors have been re-calibrated. Front and rear? Testing them isn't that hard in that you can park the car on a hill with the engine and headlights on. The headlights should point in the forward direction of the vehicle.

Another approach is to disconnect all sensors and dampers (the car will throw multiple codes). Attach one damper, test, then attach a sensor, test. The idea here is you are testing not only the sensor but whether there is a short to any part of the system causing it to go haywire.

The next step is to check the wiring. To do this properly though, an oscilloscope would be a fantastic tool to help. Unfortunately, such tools are not cheap. Seek out an automotive electronics expert who can sniff the CAN bus for random garbage rather than a regular signal expected. Most mechanics, including the dealer, often do not have the experience or tools to properly do such diagnosis so it's not a surprise to hear the shops you visited missed it. You may have to seek out a specialist.

Another possibility is rusted or broken pin on a connector. You'll need to check all related modules and each connector to it, including the connectors to each damper. Rusted pins will generate inconsistent results and broken pins will shutdown parts of a system. Generally in vehicles with a sun roof (like the X5) there will be a drain that passes from top to bottom for the water to exit. If the drain pipe cracks, water or high levels of condensation end up in electronically sensitive areas. In general, when you check any module, pull out it's connectors and look for rust or broken pins. BMW sells connector pin repair kits for a reason. It's not a shock to see a dead pin, at least on a BMW.

Good luck.
Hi thank you very much for your detailed response, that's what i love about forums.

I think you are absolutely spot on about car using substitute values due to information not available.

Unfortunately, the only thing i haven’t change is BDC (Body Domain Controller) and Ride height sensors and front shock absorbers.

BDC is above ICM from hierarchy point of view so I think it is related but not part of the system. And to change BDC you will need to involve immobiliser and all sorts but module responses fine and communicates fine and no fault codes against it, and given it controls a lot of modules I think I would have had bigger problems if that had an issue.

As for the ride height, ISTA guides you through it, you park it at level surface, measure the distance between edge of rim and fender and you put those in to the tables ISTA asking you to do it and it adjusts it self.

I can communicate with each ride height sensor and can see they are showing the ride height and headlights adjusts themselves like you said.

I checked all the connections to the shocks and the accelerometers ( accelerometers changed anyway) and they are all clean. Connection to Electronic Height Controller and VDC, ICM are also all clean.
Im struggling to find a good technician who can actually diagnose flex ray communication.
I thought of buying an oscilloscope to read signal but unfortunately even if I invest in one I don’t have a good wave form to compare to see if its how it should be.

You are right about main dealers too, i spoke to another one today local to my workplace and service adviser struggled to understand there still could be a fault with car even if there is no fault codes. Their attitude towards it that no codes no problem.


One chap who were in same situation said it was a faulty shock but how one goes diagnosing it as the only thing electronic is the valve.

Last edited by F15er; 08-23-2022 at 01:33 PM..
Appreciate 0
      08-23-2022, 02:14 PM   #86
casualDIYer
Major
428
Rep
1,359
Posts

Drives: 340i xDrive M Sport
Join Date: Nov 2008
Location: Toronto

iTrader: (0)

I'm struggling to find a good technician who can actually diagnose flex ray communication. I thought of buying an oscilloscope to read signal but unfortunately even if I invest in one I don’t have a good wave form to compare to see if its how it should be.


FlexRay on the F15? I thought that was only on the 7 series but it makes sense all cars are moving from CANBUS. You will need someone with experience though. A few videos on YouTube show there are a lot of differences in signal so someone who can differentiate treasure from trash may be worth the cost.

You are right about main dealers too, i spoke to another one today local to my workplace and service adviser struggled to understand there still could be a fault with car even if there is no fault codes. Their attitude towards it that no codes no problem.


A lot of auto systems tend to work independently to ensure one doesn't trash the other if they fault. Could BMW have installed parts so new they had no APIs on the diagnosis side to read back errors? Perhaps. What the version of iDrive you are running and is there an update? Or, the shock simply isn't sophisticated enough to send back an error. It's valve open. Valve closed.

One chap who were in same situation said it was a faulty shock but how one goes diagnosing it as the only thing electronic is the valve.

Guessing, I could imagine 4 pins for the damper. Power, ground, activate (open/close), and state (open/closed) but maybe state could be done in the third pin. The 4 may share a common ground, so if one pin is shorted out on any damper, none of them work. You may be able to test this by unplugging all 4 dampers, being sure to zip tie connectors if lose. You don't want then caught in the wheel during testing. Connect one damper and see the result. Nothing happens? Unplug that damper (because the first damper may be the faulty one) and try another. For the next test, try the damper on the opposite wheel but same axle. Ideally you will find a pair of dampers on the same axle, making it easier to tell if the ride quality is changing. I know on the Bilstein EDC dampers, they had a problem with the connector housing cracking and had a recall. Could this be a similar issue?
__________________
340i xDrive (F30), 228i (F22), 320 (F30), 325i (E46)
Appreciate 0
      08-23-2022, 02:53 PM   #87
F15er
New Member
United Kingdom
5
Rep
17
Posts

Drives: BMW X5 30d MSport
Join Date: Jul 2021
Location: United Kingdom

iTrader: (0)

Yeah FlexRay is utilised for comms between VDC (aka EDC) and ICM and the accelerometers but cant remember what else exactly.

I am going to try some auto electricians locally to see if any of them wants to tackle the job. Car is runing on Idrive 4 but Ilevel is up to date, I tried flashing it on Sunday (just reinstall of latest version) but made no difference.

I unplugged the front right valve about half an our ago as i never tried that before and car thrown up an error straight away so it knows when one is unplugged, it is only twisted pair to the shock so i believe one is ground and other is voltage.

Scanned the car to see what repair ISTA will suggest after i unplugged the valve and read following statement on system function description.

"Fail Safe
Depending on the type of fault that has occurred, the fail safe takes effect in 3 stages:

Stage 1: substitute values
if for example the signal from lateral acceleration sensor is not available, other parameters are used as substitute values for the identification of cornering. The driver does NOT receive a Check Control message: no fault entry (only a slight loss of comfort is perceptible)"

I think this is exactly going on with my car given everything i gone through and the fact that there are no fault codes.

Other stages will display check message and will go medium to hard comfort and i experienced that by unplugging one of the accelerometers and that feels like driving a tractor plus car complains about chassis restriction.

I had the rear shocks replaced with some low mileage ones ( they were only done 2.5k miles) and that made things worse as they had less wear where my original shocks already done 80k so they were more worn thus softer. I put my originals back after suffering 3-4 months as the back axle was unbearable stiff.

I believe dampers are made by Tenneco or Monroe.
Appreciate 0
      08-25-2022, 08:56 AM   #88
kilogram
Private
70
Rep
79
Posts

Drives: 340i xDrive
Join Date: Jan 2020
Location: Commerce City, CO

iTrader: (0)

Quote:
Originally Posted by F15er View Post
Yeah FlexRay is utilised for comms between VDC (aka EDC) and ICM and the accelerometers but cant remember what else exactly.
I was assuming the accelerometers were PSI5, based on what I had found for Bosch's datasheets.

Maybe the newer Keysight scopes have the data frame definitions for Flexray? The ones we use at work have defs for most other comms, you just tell it what kind of signal you're reading and it parses out the frames automatically. Then again, ours are in the $5k range so they're not cost effective to buy for this, but maybe you could grab one from Electrorent for a few weeks/months to sort it out?
Appreciate 0
Post Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 04:36 AM.




f30post
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST