Show of hands… Adaptive Suspension

[SteveSchweer]

How many new Model S owners out there can actually FEEL the difference between “Sport” and “Comfort “? I know I can’t.… even though Tesla Service says it is functioning normally. No matter what I do with the suspension controls, my ride is the same… punishingly harsh. Yet, from these forums and YouTube, I see that many of you think the suspension is great. As this is probably one of the most sophisticated suspensions ever put in a car, I have trouble believing that mine is “functioning normally “. I think the key objective question here is “can you actually FEEL a difference in ride quality when you change suspension modes?” (By ”feel” I mean you KNOW it changed, if you just THINK it changed then it didn’t). It would really help me and, I know, a number of others out there to find out if our suspensions are screwed up or if that’s just the way they are. Thanks for any input you can provide.

 

[SteveSchweer]

We will be anxiously awaiting your feedback. Thanks!

OK… I picked up the car and, as usual, the results are mixed. As I mentioned, they replaced the “Air Suspension ECU”. This DID make a major difference in the general ride of the car. It now feels like the car actually HAS a suspension. The short sharp shocks are absorbed pretty well… you hear them, but they don’t punch you in the kidneys like they used to. So, if the roads are just normally bad, ie. the occasional pot hole or expansion gap, the car rides acceptably smoothly. The problem is that the damping is still too stiff, or the suspension travel is too short, to do much with bigger, slower imperfections in the road. Things like depressed man hole covers, or poorly done patches that aren’t at grade level. These still cause the car to pitch back and forth, albeit not quite as violently as before. The irony here is that my test to determine whether the adaptive suspension was working or not (ie. You KNOW that it changed when you switched from Sport to Comfort) is still a “Fail” for my car.… you can’t easily detect that anything has changed when switching modes! It makes me think that maybe the system isn’t calibrated correctly…. Ie. If the solenoid valves are fully closed at 0 volts and fully open at 12 volts, this system is only operating in the range of 0 to 3 volts. Note Pengy’s readings (previously in this thread) that were all under 3 volts. I wish I knew how to find out what the actual range is for these shocks. I’m considering doing a complete voltage range reading on my car.. I just have to figure out a suitable way to connect my meter.

 

[Zcd1]

Thanks for reporting the results. I'm an interested observer as this is the first car I've ever purchased without a test drive, and a smoother ride than my previous Model 3P is one of the things I was hoping for with the MSLR...

 

[pengy]

It's definitely way smoother than a M3/P but don't expect it to be S class or Lexus LS levels. Steve's summary is what I feel in the car too, where large bumps just aren't absorbed that well.

 

[Zcd1]

It's definitely way smoother than a M3/P but don't expect it to be S class or Lexus LS levels. Steve's summary is what I feel in the car too, where large bumps just aren't absorbed that well.

Good to hear overall. I wouldn’t want a car that rode like either of those, so hopefully the MSLR will fit my bill.

Also hoping that the damping improves via OTA updates…

 

[pengy]

Might be a relevant error that shows up on my vehicle in service mode plus (Requires Toolbox 3 subscription and $700 ethernet adapter for car)

 

[SteveSchweer]

Might be a relevant error that shows up on my vehicle in service mode plus (Requires Toolbox 3 subscription and $700 ethernet adapter for car)View attachment 790853

Wow! Any idea what CAN and DAS stand for? Also, tell me more about “service mode plus ”… does it allow you to interrogate the operation of the car’s various systems? … like the ECU.

 

[pengy]

Wow! Any idea what CAN and DAS stand for? Also, tell me more about “service mode plus ”… does it allow you to interrogate the operation of the car’s various systems? … like the ECU.

CAN is "controller area network", it's the communication system for the car. DAS is driver assistance system. Service mode plus is a mode you can put your car in to view service type information using a tesla specific tool. That same tool can do checks on all systems and shows alerts that are not visible to the end user

 

[SteveSchweer]

CAN is "controller area network", it's the communication system for the car. DAS is driver assistance system. Service mode plus is a mode you can put your car in to view service type information using a tesla specific tool. That same tool can do checks on all systems and shows alerts that are not visible to the end user

This is interesting in light of the statement that the service tech. that worked on my ECU made: he said that Tesla changed the communication protocols sometime in the 4th quarter last year. This is part of what constitutes a 22 vs. a 21 Model S. Since my car was assembled around Thanksgiving, it occurred to me that it might be possible to get a “hybrid“ build with “old” components and “new” communication protocols… and resultant malfunctions. Does this error come and go, or is it always there?

 

[SteveSchweer]

CAN is "controller area network", it's the communication system for the car. DAS is driver assistance system. Service mode plus is a mode you can put your car in to view service type information using a tesla specific tool. That same tool can do checks on all systems and shows alerts that are not visible to the end user

How do you KNOW all this stuff? In my experience Tesla guards the information about the inner workings of the car like State secrets. Can you give me any references to your sources? Also, I noticed that in the picture you posted showing your hookup to the shock solenoid, what appears to be a plug of the type used by Tesla… if it is, could you please tell me where/how I can get a plug/socket pair?

 

[pengy]

How do you KNOW all this stuff? In my experience Tesla guards the information about the inner workings of the car like State secrets. Can you give me any references to your sources? Also, I noticed that in the picture you posted showing your hookup to the shock solenoid, what appears to be a plug of the type used by Tesla… if it is, could you please tell me where/how I can get a plug/socket pair?

https://twitter.com/x/status/1334564079264993281

You can find the plug by accessing the service manuals (I paid for a 3hr US subscription). I used some random pins I had that happened to fit.

 

[SteveSchweer]

THE RESULTS ARE IN! I did a serious attempt at documenting the operation of the system. I used my oscilloscope to measure the voltages applied to the shocks. It turns out that they are operated by varying the duty cycle of a fixed voltage (16v. 1Khz ) signal. This is not to say that they open and close a thousand times a second… I believe that they take around 6ms to move in one direction, but that they respond to the average power they are receiving. In any event, I tested them in all suspension modes while actually driving and found that, unsurprisingly, Comfort Mode really IS an illusion. Ironically, at least in my car, the SOFTEST suspension setting is Sport! I am convinced that this is a firmware problem. It will have to be communicated to Tesla’s software people. To that end, I made a YouTube video showing what I did and the results. My plan is to call Service and ask them to forward a link to the video to the appropriate people at Tesla. Let me know what you think before I do this. SO, you’ve read the book….. now watch the movie! Here’s a link:

 

[emailforbrett]

g Readings

I have the same issue. I recorded g readings for the sport and comfort settings. I can feel no difference In the ride. The ride is too stiff in any setting. I did find in the softest mode, the car registered about .5 g more bounce over the speedbump. The opposite of what I should have experienced.

 

[SteveSchweer]

g Readings

I have the same issue. I recorded g readings for the sport and comfort settings. I can feel no difference In the ride. The ride is too stiff in any setting. I did find in the softest mode, the car registered about .5 g more bounce over the speedbump. The opposite of what I should have experienced.

Your readings match my findings…. “Hard” mode provides about a 10% duty cycle whereas “soft” provides 0%, thus, hard is softer than soft!

 

[ShawnA]

Hi @SteveSchweer ,

I enjoyed your movie and applaud your research!!!
Did you see a part number for the "Air Suspension ECU" on your Tesla paperwork?

Would you classify the waveform and action a PWM type of control?

Thank you,

Shawn

 

[oktane]

Your readings match my findings…. “Hard” mode provides about a 10% duty cycle whereas “soft” provides 0%, thus, hard is softer than soft!

Give it a 50% duty cycle if you need some fillings removed

 

[pvdoug]

THE RESULTS ARE IN! I did a serious attempt at documenting the operation of the system. I used my oscilloscope to measure the voltages applied to the shocks. It turns out that they are operated by varying the duty cycle of a fixed voltage (16v. 1Khz ) signal. This is not to say that they open and close a thousand times a second… I believe that they take around 6ms to move in one direction, but that they respond to the average power they are receiving. In any event, I tested them in all suspension modes while actually driving and found that, unsurprisingly, Comfort Mode really IS an illusion. Ironically, at least in my car, the SOFTEST suspension setting is Sport! I am convinced that this is a firmware problem. It will have to be communicated to Tesla’s software people. To that end, I made a YouTube video showing what I did and the results. My plan is to call Service and ask them to forward a link to the video to the appropriate people at Tesla. Let me know what you think before I do this. SO, you’ve read the book….. now watch the movie! Here’s a link:

I just found this thread, although there are a number of similar ones. There is one entitled "Bouncy Suspension Model S" in which I responded:
"My 2022 MS is awful at speed bumps [and I go thru many daily just to arrive at my condo complex]. I go slow and it is still horrible. I went in for service yesterday and took a ride both with the tech and his superior. They both said it was within range. The latter said that Tesla may come out with a software fix. I do not have a problem with that aspect of the car otherwise. I am sure that if I reduced the air pressure in the 19 tires it might alleviate the situation, but that may cause other negative issues. I drive in the Comfort mode. I have been driving a 2001 V6 Honda Accord for the last twenty two years and I had higher expectations from Tesla. Still an amazing vehicle, but with many unnecessary and frustrating flaws."
So thanks for your great video. I will be monitoring this thread in the hopes of a supportive response from Tesla.

 

[SteveSchweer]

Hi @SteveSchweer ,

I enjoyed your movie and applaud your research!!!
Did you see a part number for the "Air Suspension ECU" on your Tesla paperwork?

Would you classify the waveform and action a PWM type of control?

Thank you,

Shawn

Thanks Shawn! I guess it is a form of pulse width modulation… at a VERY low frequency. I would say that it’s more like the DC equivalent of an SCR controlled dimmer circuit. The part they replaced was :
ASY, ECU, MODEL S, 1.00 TASC 2.0(1134794-01-
D)

 

[pengy]

PWM Solenoid Theory | TLX Technologies

Pulse Width Modulation Solenoid operation uses a DC supply voltage that is switched on and off at a given frequency for a modulated period of time (duty cycle).

www.tlxtech.com

The signal is PWM driven but when driving a solenoid, it behaves like an analog flow valve.

I think you'd have to get the duty cycle while driving, which is a bit more difficult to really tell what the car is commanding the solenoid to do. Some reports say 0% is no damping, some say 100% is no damping.

 

[SteveSchweer]

PWM Solenoid Theory | TLX Technologies

Pulse Width Modulation Solenoid operation uses a DC supply voltage that is switched on and off at a given frequency for a modulated period of time (duty cycle).

www.tlxtech.com

The signal is PWM driven but when driving a solenoid, it behaves like an analog flow valve.

I think you'd have to get the duty cycle while driving, which is a bit more difficult to really tell what the car is commanding the solenoid to do. Some reports say 0% is no damping, some say 100% is no damping.

I did observe the duty cycle while driving (I used an inverter to power the scope). I didn’t video it, as it was too difficult to jury rig a camera mount that would hold everything steady enough on bumpy roads… where the duty cycle changes. What happens is this: A “base value“ duty cycle is set upon selection of a ride mode. This duty cycle never goes below the base value, but will increase 10 to 20% as bumps are encountered. As to the duty cycle vs. damping question, I can testify, from bitter experience, that with a broken ECU, (as I had, thus, 0% duty cycle) the result is max damping… the harshest ride possible!
I contacted Service yesterday. They gave me an email address that they said was “generally visible” in their service center. I wrote a short cover note describing my problem and included a link to the video. Hopefully, someone will pass it on until it reaches the proper department…. Rather like putting a rescue note in a bottle and tossing it in the ocean. I think it would be good if EVERYONE who has this problem would do the same. If Tesla gets the same video sent to them from 50 different people it might raise the urgency to do something about it!

 

[Unclepaul]

This is all quite different than my experience in my 2019 Raven X. Comfort felt smoother, Firm felt more controlled.

After a bit, I would simply leave it in automatic for a fantastic experience. At low speeds and just cruising around it gave a soft, smooth and quiet ride. When I would drive at higher speeds or on curvy roads the suspension would firm up significantly to provide better control. Most amazing results were seen when cruising at high speeds along sweeping curves. It did not bob or sway, but carved up the curves, feeling great along the way.

Thought this suspension was the best of all worlds, from a travelers perspective.

Hope the OP gets his sorted out, because when it is operating properly the combination of soft when going slow, but firm when going fast is quite remarkable.