Ok I finally have narrowed down my problems with the compressor coming on constantly . Have really studying the flow chart I decided to look into the ADS system damping valves front and back…brand new front struts with ads. Older rear struts with ads… my Launch x-431 can test the 2 valves per strut.. rears work perfect turn on and turning off basically 4 valves in the rear (2 per side)
The fronts are a mess… 1 side has one valve working with the wrong control and the other side is flaky .. according to my flow chart all 4 Y51,Y52,Y53,Y54 are hard wired to the N51 airmatic controller under the driver seat.. I tried a used controller same results..
Any ADS (damping valves on the struts) experts especially on wiring and similiar problems PLEASE send info… going to have to start looking into wiring and praying it’s not the PCM
Has anyone successfully deleted the damping valves with Star and the airmatic system ? Some airmatics come without the damping .. sure would be a lot easier to get rid of this headache if I can get rid of the damping valves…

 

Does anyone know what state the ADS valves are in ?
NC or NO?
I am seriously considering attempting to try and delete the ADS system (pulling power? and wanted to know if anyone knows if the valves are NO or NC with no signals … thanks Bill

 

Are you sure that all four struts actually have damping valves?

some aftermarket solutions just have a resistor that mimics the multiple valve settings so that the ADS control module thinks everything is per spec - when in reality you only have one mechanically set damping rate.

if you have different struts on each corner you could therefore have different damping rates at each wheel.

this is cool in circle track roundy round racing like nascar but results in unpredictable handling in daily driving.


I don’t know if your tool can do this but in MBstar developer mode it should be possible to tell the car it is a non-ads car and thusly defeat the system. But you’re then stuck with unknow damping rates at each corner. Fix for that is four new $truts….

 

Thanks for the input… I was chasing a mistake for a day. My new Launch 431 bi-directional OBDII toy has a problem.. it gave me false readings about the front ADS (new Bilsteins) and said the back ads struts were good. After doing the test multiple times .. I than believe there was maybe a wiring problem..This morning I brought the Star laptop setup and all ADS valves tested fine.. Launch issue…
The GL is still continuing to pass all airstrut test.. but on the road the compressor is running as soon as I hit 25 mph … I am officially stumped and going to see a dealer next week. Something is telling the compressor to turn on and it is definitely not needed to run… all 4 corners are fine… no leaks . The odds that the old valve block and new RAPA valve block are both bad?
Possible one of the 4 hall effect level detectors have a dead spot and turning the compressor which now runs for over 30 seconds … as does it everytime I slow down (shutoff at 10mph ) than turns back on at 25mph. ???? any thoughts I am all ears

 

I was on MMHAUTO forum reading and asking more questions.. the only reasonable line of thinking was that the Level Calibration was thrown off by installing a new compressor ?? Makes NO logical sense right? That was all that was changed that brought on the compressor running way too much and a few Reservoir pressure readings that were not maxed out… instead of 16 bars.. some were 7,8, 12 and 13 rarely 16. Down the rabbit hole changing a few parts … valve body than the new Launch 431 meter sent me into ADS issues that were fine … my mistake for getting away from the Star system ( but the small handheld Launch is so easy and quick ).
Ok attached will be a picture of how to measure rear angles with an iphone / app for bubble angles.
Huge improvement on the compressor run time and reservoir pressure is back to normal 16 bar.
Since the system is still running everytime at a new startup at 25mph I am taking in to a dealership for a Level Calibration on an alignment machine with a big buck angle reader (Romess meter) … it’s very hard to get an iphone on the front axles … with a little machine shop time a plate could be made to use an iphone… laying on the ground sliding along the floor having someone run the 4 corners up/down to get the angles right etc etc.
The biggest reason I am going to a dealership is I have to know why this happened changing a compressor … or how did the airmatic computer board lose the calibration ???
For whoever is left following this saga thanks for all the reading …. for more laughter while pulling the power (disconnecting the battery ) on power up my command radio now won’t eject CD’s and runs and runs…. got to love these machines…. complaining to the dealer the feedback was …you should see the new headaches the newer models have ..
I feel better now 😂

 

Are you hearing a lot of off board venting when you stop?

And have you done a live read out of voltages in MB star while rocking the vehicle?

One of the voltage completely out of spec with the other others may indicate that your level sensors or level sensor arms are out of whack.
Some of the sensor arms can go rubbery over time and cause incorrect readings, commanding the system to inflate when it in fact it isn’t needed.

If you have a Das system, the dealers is not gonna be able to do anything that you can. Just do the automatic calibration on a level surface, measure the distances between the wheel arch and the top of the wheel.

You use a lot of words and I’m a TLDR guy ( hard to discern the basic facts) but what I’m getting is that everything is new there are no leaks yet. Your compressor is running all the time over 25 miles an hour.

It is normal that the compressor only runs over 25 miles an hour so that it isn’t heard as much.

if you’re hearing copious venting when you shut, the car off means that it is in fact over inflating.

so you may have two separate problems here, ADS and airmatic are two very separate systems yet they integrate on the front struts.

The two core complaints is that you feel your compressor runs too much, this is an airmatic issue
and two; what’s wrong with ADS?

 

1. NO leaks
2. Not much venting at all just normal open door woosh
3. All level sensors working .. arms greased and solid
4. Changing a compressor or sensors can throw off the calibration… according to my research
5. I did the calibration and it helped a lot
6. I found a nice small digital level that will go magnetically on each axle …
7. The Mercedes shop will do all the work in an alignment shop and at $179.. it’s worth saving a compressor.
8. I am hoping the dealer can explain or have them talk to a mercedes suspension expert and at least explain why changing a compressor will and can knock off the level????

 

So compressor characteristics can throw off the level calibration and that is what I chased for weeks. I found many people online that did the same mistake…

 

Well, for what it’s worth I never recalibrated this one after changing the compressor about a year ago. No issues with automatic at all, and it sort of finds its own level over time.

 

Max this is my third air suspension 164… changed struts and compressors in the first 2 without a problem … that is why this sob threw me for a loop..
All I can do is warn the group and do my best with documentation on what I am doing. thanks again for sticking it out and following me thru this ordeal .

 

For anyone following this thread don’t be afraid to PM for air suspension info.
1. i did a level calibration at home … according to the dealership… I had the front within 2-3mm of correct factory specs… the back was off about 15-20 mm.
Once the shop did a complete factory reset and we decided to add some new compressor mounting hardware ( I barely hear the compressor now) . After 3 days of running errands about 200 miles total .. the compressor has run a total time of 8.5 minutes or 520 seconds.
2. According to my older 550 that I wrote down all the compressor times between oil changes … that averaged about 1.5 hours a month…so this one is lining up about the same .
3. The shop mechanic that did the level calibration just referred to the factory level similiar to a CNC machine needing its zero calibration for all the axis.
4. I have changed air suspension parts on my other 2 MB’s and never needed a calibration… this one really threw me into a frustrating learming curve.
5. If I can help anyone please reach out … i did a lot of reading and downloading of info trying to solve this fiasco.

 

can’t help with no nc but I tried to delete. Tried big resisters of the same resistance as coil and after a while I would get a error message unless it was in sport mode. This could indicate that no power is sport. Assume that could be closed (offering more resistance). So possibly nc

 

My ads problem was solved because My Launch 431 was in error . Once I hooked up the Star system everything tested ok. thanks Bill

 

What coil? The main one inside the sensor? (I assume its a potentiometer) That is a variable resistor, as in always changing its Ohm value. Installing a fixed resistor would throw an error, because the system isn't seeing that sensor changing values anymore.

Maybe Sport mode is full low or the highest resistance for the sensor, so that's why it works in that mode?? The system is looking for the highest resistance, so no codes.


When I bought that Foxwell scanner and recalibrated my wifes system, when it asked for the degrees to save the new height, I just added almost the highest number allowed. Seemed to work.

 

the coil in the valve in the shock absorber/damper

the ads is adjustable damping. Not ride height

 

For those that get involved in doing a level calibration here is a link on a another chassis just to give you a little visual on the front and rear angles… you don’t really have to guess and put in a value… you can measure the degrees. You can use an iphone with an app … I also found a nice small measuring device
.. will include a picture from Amazon.


https://w220.wiki/Angle_Measuring_De...r_Inclinometer

 

Where are you placing this? What angles are you supposed to measure? It was something like -3 deg to 5.5 deg or something like that from front and rear. Not sure what you are suppose to measure, so I just guessed.

 

Take a look at the article for the W220 chassis and it will become much clearer . You are measuring the axle angles … Front L &R…. Rear L&R
Also you want the car sitting perfectly level…. setting the front and rear height to factory specs … than read the front and rear angles … put all that info into the bi-directional reader … Star.. Launch …etc

https://w220.wiki/Angle_Measuring_De...r_Inclinometer

 

“The rear of a Mercedes-Benz X164 chassis sits slightly higher than the front in a stock, level setting.
Typical ride height measurements from the wheel center to the fender arch are approximately:

• Front: 485mm to 510mm
• Rear: 500mm to 525mm
• When I got home last week from the dealer after setting my GL550 to factory level calibration my car sat approximately 19” in the front and 19 5/8” in the rear … which is approx 485mm front and 500mm rear.
• While you are setting the height with the laptop or launch controls (in manual setting) you should monitor the AXLE angles… it is not a 5 minute quick job … everytime you change the front or rear it will effect the other axle and everytime you set the left side the right side is effected.

 

Oh, well, thats not how I did it. I manually operated each bag until the wheel gaps were equal, then plugged in some randon angle and hit save. Seemed to work lol. Took about 15 minutes.

So what does the actual angles tell the system?

 

The rear should sit slightly higher. The last couple of post took a lot of research. Than I followed up with a dealership calibration. I called 5 dealerships and went with the one that let me talk to the tech and gave me all the specs . It was well worth to spend $179 . There was not a definite answer on why some airtronic boards need a level calibration after changing a compressor or struts??????? It definitely got me back on the road .
I already stated that my first 2 air suspension 164’s after changing struts and compressors never needed a calibration .

 

Calibration Process

1. Vehicle Preparation: Park the vehicle on a level surface, ensure the tires are at the correct pressure, and the vehicle is fully unloaded. Roll the vehicle back and forth to allow the suspension to settle.
2. Diagnostic Tool Connection: Connect a diagnostic tool (such as Mercedes Star Diagnosis/XENTRY, Autel, or Youcanic scanner) to the OBD-II port.
3. Access Suspension Module: Navigate to the "Chassis" or "Air Suspension" control module within the diagnostic software.
4. Initial Startup/Calibration Function: Select the "Initial startup" or "Level adjustment" function, often followed by "Manual settings".
5. Take Measurements: Use the inclinometer tool at the designated points on the front control arms and rear axle shafts to obtain the precise angle readings (in degrees).
6. Enter Values: Input the measured angles into the diagnostic software when prompted. The system uses these values to determine the correct "zero" point for the level sensors.
7. System Adjustment: The system will then automatically adjust the air suspension to the specified ride height based on the entered angles and the live data from the level sensors (which typically read around 2.5V at normal height).
8. Finalization: Exit the diagnostic software, turn off the ignition, and allow the car to settle. The calibration should then be complete.

 

Bad information from a junk system?

 

No doubt I would not rate Launch very high. I wrote to Launch USA today and they told me my serial number was not covered under there support because it was bought on ebay.
I was after a small handheld bi-directional to take on road trips . Also air up struts if needed.

 

I have this one, it was a little over $300 on Amazon, comes with a case you could put in the spare tire well. Roughly the size of an iPad mini, fully bi-directional. I like how its always updating as well. Just right now when I powered it up, there were two updates, one for the main OBD2 system and one for Sprinter. Nice that there are constant updates at least, AND NO FEES, I hate that some systems have yearly subscription fees.