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I’ve had this issue on my 06 E55 where my suspension feels super stiff. My 049 B7 Airmatic pressure sensor is only showing about 2 bar, I know it should be higher so
I scanned my friends 07 E63 to confirm and his pressure is at around 10 bar. What’s the remedy here? Replace the sensor? I believe it’s part of the valve block by the compressor so not sure if the sensor can be changed on its own. Or is this a compressor issue? Car raises up fine and gives no other indication of a weak compressor or low pressure anywhere which makes me think the sensor is reading the pressure wrong, and maybe pumping more air to compensate, resulting in the stiff suspension. I just changed the airmatic filter since it’s cheap and at 120k miles it was overdue, but as I expected, nothing improved. Thoughts?
You are reading the live data, not fault codes. Is the sensor faulty or not? If no sensor fault code, live data indicates first candidate is the air compressor, second is pressure relief valve, third is air leak that closes off at just under two Bar.
Suspension feels stiff because you are riding on the bump stops and destroying your air springs. If ride height is under 26" fender roll to ground, you are out of spec. 1.92 Bar is less than what WIS calls for to initially inflate air springs on installation.
Xentry ride level test calls for +/- 3mm optimum. Check that out.
Anyone else feel free to chime in. I could be wrong.
Last edited by bbirdwell; Nov 15, 2024 at 10:36 PM.
You are reading the live data, not fault codes. Is the sensor faulty or not? If no sensor fault code, live data indicates first candidate is the air compressor, second is pressure relief valve, third is air leak that closes off at just under two Bar.
Suspension feels stiff because you are riding on the bump stops and destroying your air springs. If ride height is under 26" fender roll to ground, you are out of spec. 1.92 Bar is less than what WIS calls for to initially inflate air springs on installation.
Xentry ride level test calls for +/- 3mm optimum. Check that out.
Anyone else feel free to chime in. I could be wrong.
I was going based off of live data because there are no fault codes, even after months of driving. Ride height is at normal level and stays at normal level, never sags. That’s the odd part, the only anomaly in the live data, including voltages, acc sensors, level sensors, etc., is the 2 bar on the pressure sensor. The compressor works just fine when I raise the car either with the lift button inside or with my scanner (also seems to relieve pressure and lower fine), however the compressor output being weak but not obviously noticeable is possible I suppose.
What are the pressures in the reservoir and the individual air springs? Can your diagnostic tool read those pressure sensors? If they are all right around 2Bar, I would say bad compressor but then run in Xentry a compressor test that measures how fast the pressure rises within a specified period of time. A failing compressor will not throw a code; all you can do is measure the output pressure rise versus time.
Arnott sells compressors; I purchased one from them that was OEM provider from Germany. When removing the old compressor, very carefully observe (and photograph) the way the washers and suspension springs are installed. It's a PITA to hold the compressor up with one hand while trying to install the springs and washers that hold the compressor to the frame.
Last edited by bbirdwell; Nov 16, 2024 at 02:38 PM.
What are the pressures in the reservoir and the individual air springs? Can your diagnostic tool read those pressure sensors? If they are all right around 2Bar, I would say bad compressor but then run in Xentry a compressor test that measures how fast the pressure rises within a specified period of time. A failing compressor will not throw a code; all you can do is measure the output pressure rise versus time.
Arnott sells compressors; I purchased one from them that was OEM provider from Germany. When removing the old compressor, very carefully observe (and photograph) the way the washers and suspension springs are installed. It's a PITA to hold the compressor up with one hand while trying to install the springs and washers that hold the compressor to the frame.
Now when I check, all 4 sides show exactly 5.76 bar, not sure if it’s normal for them to be the same. I couldn’t find the pressure for the reservoir unless that’s the 049 B7 sensor. My scanner does have the compressor test function and it passed without issue, rose up to 14 bar within a few seconds. I have noticed lately that the car will lower an inch or so below my calibrated level evenly on all sides after driving. No obvious leaks anywhere.
FWIW, all of my air springs show 5.7 - 5.8 Bar. Minor variations in pressure. Perhaps it is a bad sensor. Check the electronic parts catalog to see if it is available separately or only as part of the valve block assembly.
FWIW, all of my air springs show 5.7 - 5.8 Bar. Minor variations in pressure. Perhaps it is a bad sensor. Check the electronic parts catalog to see if it is available separately or only as part of the valve block assembly.
Ahh that is interesting, I figured it was strange the pressures were the exact same. I’m leaning towards an electrical issue rather than a mechanical fault with the struts/ bags Will definitely look into it, at this point I’m down to spend the money on whatever as long as it’s going to solve my issue. The ride quality is absolutely nauseating.
I’ve had this issue on my 06 E55 where my suspension feels super stiff. My 049 B7 Airmatic pressure sensor is only showing about 2 bar, I know it should be higher so
I scanned my friends 07 E63 to confirm and his pressure is at around 10 bar. What’s the remedy here? Replace the sensor? I believe it’s part of the valve block by the compressor so not sure if the sensor can be changed on its own. Or is this a compressor issue? Car raises up fine and gives no other indication of a weak compressor or low pressure anywhere which makes me think the sensor is reading the pressure wrong, and maybe pumping more air to compensate, resulting in the stiff suspension. I just changed the airmatic filter since it’s cheap and at 120k miles it was overdue, but as I expected, nothing improved. Thoughts?
UPDATE, SOLVED:
I figured it out and it’s embarrassing to say the least. I had some ESP codes stored from when I had disconnected some things a few weeks ago that were forcing the car into the super stiff suspension “safe mode”. Cleared the codes and it’s good again. I was 100% positive I had cleared the codes prior to all of this but evidently not, caused myself a ton of stress for nothing!
2006 CLS55 IWC, 2003 Black E55 designo interior, 2005 White designo E55
I noticed I've got less than 3 bar at the B7 pressure sensor. Already installed a new genuine valve block. Every corner and the compressor have only got about 20k miles on them but they're about 5 years old.
My other 55 has over 10 bar I think at the B7, that compressor is 2 years old, maybe 5k miles.
I may change the compressor and see what happens to the B7 pressure value.
I have no ESP faults or any other drive related faults.
If the compressor doesn't fix it, I am likely removing all airnaticame from this car. And if I like the ride quality and height, I may just do this to my other 55.
2006 CLS55 IWC, 2003 Black E55 designo interior, 2005 White designo E55
So finally got my star diagnostics working again.
Compressor builds pressure very quickly. This compressor is less than 10k miles on it and 2 years.
However, pressure relief is almost nonexistent. So I am taking a look at the relief valve on the compressor as maybe some moisture got in there and caused some corrosion.
2006 CLS55 IWC, 2003 Black E55 designo interior, 2005 White designo E55
By the way does not lower when commanded via Star. Inflated every corner very quickly. But no release. Also front right voltage is well below the minimum of the range. Will update when I'm sure it's fixed, for anyone else it may help.
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