The ABC Suspension Thread
Member
Joined: Feb 2018
Posts: 227
Likes: 55
CL500, W212 e350 mega-spec
yeah, it was the bearing I was most keen on changing. The parts suppliers call it a clutch but I can well imagine it's simply because so many other AC compressors have that part as the clutch. Usually there is a wire running under the pulley to activate a solenoid to engage or disengage the clutch but I can see from pictures of replacement compressors that this one does not have it...
Member
Joined: Feb 2018
Posts: 227
Likes: 55
CL500, W212 e350 mega-spec
Turns out some versions of the CL500 have a magnetic compressor pulley clutch and others don't. Mine does not have the magnetic clutch. I had to order twice though as the first one was a magnetic type despite being listed as compatible for my car. The second one was also listed as a magnetic clutch but wasn't. I had to use the photos to figure it out for myself which part I was buying!
Anyway, that has solved the issue which has been with me for such a long time.
I made the mistake of going down the ABC rabbit hole when it wasn't anything to do with it. The Mercedes dealer diagnosed the problem as a noisy ABC pump and would have charged the customer thousands to replace it. I paid something like £350 for a replacement pump, fitted it myself and at least I now know mine is good for a long while.
The noise was coming from the same area as the pump because the AC compressor is directly below the ABC pump.
When I got the pulley off the compressor (a bit of a fight due to corrosion) it was immediately obvious the bearing was shot.
Anyway, that has solved the issue which has been with me for such a long time.
I made the mistake of going down the ABC rabbit hole when it wasn't anything to do with it. The Mercedes dealer diagnosed the problem as a noisy ABC pump and would have charged the customer thousands to replace it. I paid something like £350 for a replacement pump, fitted it myself and at least I now know mine is good for a long while.
The noise was coming from the same area as the pump because the AC compressor is directly below the ABC pump.
When I got the pulley off the compressor (a bit of a fight due to corrosion) it was immediately obvious the bearing was shot.
Newbie
Joined: Dec 2024
Posts: 10
Likes: 0
From: Surrey
2003 cl500
ABC suspension issue
Hi all,
I'm going to attempt to revive this thread, I've got a 2003 CL500 with an ABC suspension warning (Visit workshop so not terminal) but would like to get it fixed. As a bit of backstory, I bought the car off a friend for cheap, it's low mileage, in good condition and the warning light was the only issue. Since then I've driven it and everything has been fine, the light doesn't affect the performance of the suspension and everything works as it should.
Now, for my issue. I pulled the error codes from the car and got the following: C1128 - Fault in component B22/1 (left rear plunger travel sensor), and pulled the sensor reading (It wasn't parked on flat ground but the problem is pretty obvious):
B22/1 - 255mm
B22/2 - 44mm
B22/3 - 34mm
B22/4 - 97mm
When changing the ride height of the car, the ride height on B22/1 remains the same, at 255mm. From my own research it sounds like the plunger travel sensor is completely broken, so a new suspension strut?
If I'm wrong please let me know. I've heard of connection issues being a thing but not sure if this is the case for me.
I'm going to attempt to revive this thread, I've got a 2003 CL500 with an ABC suspension warning (Visit workshop so not terminal) but would like to get it fixed. As a bit of backstory, I bought the car off a friend for cheap, it's low mileage, in good condition and the warning light was the only issue. Since then I've driven it and everything has been fine, the light doesn't affect the performance of the suspension and everything works as it should.
Now, for my issue. I pulled the error codes from the car and got the following: C1128 - Fault in component B22/1 (left rear plunger travel sensor), and pulled the sensor reading (It wasn't parked on flat ground but the problem is pretty obvious):
B22/1 - 255mm
B22/2 - 44mm
B22/3 - 34mm
B22/4 - 97mm
When changing the ride height of the car, the ride height on B22/1 remains the same, at 255mm. From my own research it sounds like the plunger travel sensor is completely broken, so a new suspension strut?
If I'm wrong please let me know. I've heard of connection issues being a thing but not sure if this is the case for me.
MBWorld Fanatic!
Joined: Oct 2021
Posts: 1,189
Likes: 636
From: Iowa
2008 CL550, 2022 EQB 300, 2023 EQS 450 4Matic
Hi all,
I'm going to attempt to revive this thread, I've got a 2003 CL500 with an ABC suspension warning (Visit workshop so not terminal) but would like to get it fixed. As a bit of backstory, I bought the car off a friend for cheap, it's low mileage, in good condition and the warning light was the only issue. Since then I've driven it and everything has been fine, the light doesn't affect the performance of the suspension and everything works as it should.
Now, for my issue. I pulled the error codes from the car and got the following: C1128 - Fault in component B22/1 (left rear plunger travel sensor), and pulled the sensor reading (It wasn't parked on flat ground but the problem is pretty obvious):
B22/1 - 255mm
B22/2 - 44mm
B22/3 - 34mm
B22/4 - 97mm
When changing the ride height of the car, the ride height on B22/1 remains the same, at 255mm. From my own research it sounds like the plunger travel sensor is completely broken, so a new suspension strut?
If I'm wrong please let me know. I've heard of connection issues being a thing but not sure if this is the case for me.
I'm going to attempt to revive this thread, I've got a 2003 CL500 with an ABC suspension warning (Visit workshop so not terminal) but would like to get it fixed. As a bit of backstory, I bought the car off a friend for cheap, it's low mileage, in good condition and the warning light was the only issue. Since then I've driven it and everything has been fine, the light doesn't affect the performance of the suspension and everything works as it should.
Now, for my issue. I pulled the error codes from the car and got the following: C1128 - Fault in component B22/1 (left rear plunger travel sensor), and pulled the sensor reading (It wasn't parked on flat ground but the problem is pretty obvious):
B22/1 - 255mm
B22/2 - 44mm
B22/3 - 34mm
B22/4 - 97mm
When changing the ride height of the car, the ride height on B22/1 remains the same, at 255mm. From my own research it sounds like the plunger travel sensor is completely broken, so a new suspension strut?
If I'm wrong please let me know. I've heard of connection issues being a thing but not sure if this is the case for me.
Newbie
Joined: Dec 2024
Posts: 10
Likes: 0
From: Surrey
2003 cl500
Super Member
Joined: Sep 2021
Posts: 537
Likes: 115
From: Ann Arbor, MI
2004 SL600
IIRC plunger travel is measured in percentage and level sensor in voltages which are then converted to mm. Fully compressed plunger travel is 0% and fully extended it is 100%. Compare plunger travel with lever sensor voltages and mm to help diagnose this.
Last edited by mrvedit; Jan 25, 2025 at 10:49 AM.
Newbie
Joined: Dec 2024
Posts: 10
Likes: 0
From: Surrey
2003 cl500
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Super Member
Joined: Sep 2021
Posts: 537
Likes: 115
From: Ann Arbor, MI
2004 SL600
Bummer. You might try swapping plungers between the struts to confirm whether its only the plunger/sensor. I cut nearly invisible slits into my carpeting so that I can easily access the struts. The strut plungers pull out easily.
IIRC a few places sell just the plunger/sensors while other sell rebuilt struts. Good luck.
IIRC a few places sell just the plunger/sensors while other sell rebuilt struts. Good luck.
Newbie
Joined: Dec 2024
Posts: 10
Likes: 0
From: Surrey
2003 cl500
Unfortunately, I believe the plunger is integrated into the suspension strut on the cl so can't be easily swapped out. Will have a look at swapping the level sensors soon but as you said, it's going to include removing some interior trim which will be a pain..
Super Member
Joined: Sep 2021
Posts: 537
Likes: 115
From: Ann Arbor, MI
2004 SL600
I just checked with a knowledgeable (but inactive) member here, who recently even sold 8 ABC struts from various CL cars, and he said the CL struts were indeed integrated. No idea how difficult they would be to disassemble to get the plunger out.
I'm still learning the difference between SL, CL and S cars with regard to the ABC system.
I'm still learning the difference between SL, CL and S cars with regard to the ABC system.
Newbie
Joined: Dec 2024
Posts: 10
Likes: 0
From: Surrey
2003 cl500
I thought that was the case, thank you for checking. Another thought though, when I plugged my diagnostic tool in the suspension seems to be 'locked' indicating i cannot change the ride height. However, the buttons still clearly work, it's not fast by any means but the height does indeed change when driving. I may have a wiring issue, so will keep on digging.
Would a diagnostic tool still 'record' the plunger travel sensor as giving a reading even with a dodgy wire? Would it give a constant reading, in this case of 255mm?
Would a diagnostic tool still 'record' the plunger travel sensor as giving a reading even with a dodgy wire? Would it give a constant reading, in this case of 255mm?
Last edited by Lpm03; Jan 27, 2025 at 12:23 PM.
Super Member
Joined: Sep 2021
Posts: 537
Likes: 115
From: Ann Arbor, MI
2004 SL600
I assume your scanner lets you raise and lower any wheel to its max? DAS/Xentry certainly does. Raise and lower each wheel while observing the plunger travel percentage. My fronts would go from 0% to 100%. The rears would go from 0% to 98% (should be 100% but that is a future thread story). On my car the motion is very quick. If slow, check your ABC pressure, should stay between 180-190 Bar.
IMHO, if the strut plungers move between close to 0% and 100% then the problem is elsewhere. Assuming the struts are leaking.
I'm still learning about all the possible ABC problems, but again IMHO, if just one or two wheels only raise slowly, they I would suspect a restriction in the line going to that wheel, likely in the valve block for that wheel.
While it may be extremely rare, lots of MB ABC owners were alarmed by the ABC problems that YouTuber LegitStreetCars found on his CL65. In case you missed those, he is an ex-MB mechanic and found rubber pieces clogging his lines; the rubber likely came from an accumulator.
IMHO, if the strut plungers move between close to 0% and 100% then the problem is elsewhere. Assuming the struts are leaking.
I'm still learning about all the possible ABC problems, but again IMHO, if just one or two wheels only raise slowly, they I would suspect a restriction in the line going to that wheel, likely in the valve block for that wheel.
While it may be extremely rare, lots of MB ABC owners were alarmed by the ABC problems that YouTuber LegitStreetCars found on his CL65. In case you missed those, he is an ex-MB mechanic and found rubber pieces clogging his lines; the rubber likely came from an accumulator.
Junior Member
Joined: Feb 2022
Posts: 20
Likes: 2
From: Houston
2005 CL600 Renntech Stage 2
Is anyone here able to recommend a good ABC mechanic in Houston? The shop I visited fixed the leak, but sy there's an issue with the passenger rear that's above their paygrade. Would be greatly appreciated. I hate having warning lights.
Member
Joined: Feb 2018
Posts: 227
Likes: 55
CL500, W212 e350 mega-spec
Does anyone know how to adjust the ride height through the computer diagnostics? I've seen a YouTube video explaining a bit about it but the guy didn't really know anything and none of the tips were of any use.
My car sits at different heights on all the different corners.
I may end up buying the adjustable level sensor arms and doing it that way but I should be able to do it for free without buying anything or modifying the car.
My car sits at different heights on all the different corners.
I may end up buying the adjustable level sensor arms and doing it that way but I should be able to do it for free without buying anything or modifying the car.
Super Member
Joined: Sep 2021
Posts: 537
Likes: 115
From: Ann Arbor, MI
2004 SL600
Using a good scanner, perform the ABC level calibration. Be sure you are on a very level surface when you perform it. It will ask for the angles of the front and rear suspension; pick the standard values and you should end up very close to level at each corner.
Member
Joined: Feb 2018
Posts: 227
Likes: 55
CL500, W212 e350 mega-spec
I already did a level calibration and set values side to side as the same but they didn't come out the same in reality.
Super Member
Joined: Sep 2021
Posts: 537
Likes: 115
From: Ann Arbor, MI
2004 SL600
Hmmm, sorry to hear that the calibration didn't work for you.
You might want to start a new thread in the general SL230 section as there are very active members there who know ABC better than me. Just a few weeks ago there was a discussion about calibration angles.
In the mean time have you confirmed that you plunger values are quite different at each corner?
You might want to start a new thread in the general SL230 section as there are very active members there who know ABC better than me. Just a few weeks ago there was a discussion about calibration angles.
In the mean time have you confirmed that you plunger values are quite different at each corner?
Member
Joined: Feb 2018
Posts: 227
Likes: 55
CL500, W212 e350 mega-spec
Hmmm, sorry to hear that the calibration didn't work for you.
You might want to start a new thread in the general SL230 section as there are very active members there who know ABC better than me. Just a few weeks ago there was a discussion about calibration angles.
In the mean time have you confirmed that you plunger values are quite different at each corner?
You might want to start a new thread in the general SL230 section as there are very active members there who know ABC better than me. Just a few weeks ago there was a discussion about calibration angles.
In the mean time have you confirmed that you plunger values are quite different at each corner?
Super Member
Joined: Sep 2021
Posts: 537
Likes: 115
From: Ann Arbor, MI
2004 SL600
Hmmm, I initially wondered if the replaced strut somehow has different plunger calibration which could result in one corner sitting too high despite all plunger levels being the same. But maybe not...
My AI search of "Mercedes R230 ABC to level the car does the computer look at plunger values or ride height" returned this result:
The Mercedes R230 Active Body Control (ABC) system primarily uses ride height sensors (one at each wheel) to monitor and maintain the car's level, which is confirmed by eBay seller 389071049347 and mri-auto-diagnostics.com PDF. While plunger sensors on the struts monitor acceleration for damping, the height sensors are the primary input for determining and adjusting the vehicle's corner-specific height.
Before reading that I thought I plunger values were the more important and that the calibration correlated plunger values with ride height sensor voltages.
Now I will have to experiment more. (Automotive AI results are often wrong.)
Crazy complicated and often frustrating system.
My AI search of "Mercedes R230 ABC to level the car does the computer look at plunger values or ride height" returned this result:
The Mercedes R230 Active Body Control (ABC) system primarily uses ride height sensors (one at each wheel) to monitor and maintain the car's level, which is confirmed by eBay seller 389071049347 and mri-auto-diagnostics.com PDF. While plunger sensors on the struts monitor acceleration for damping, the height sensors are the primary input for determining and adjusting the vehicle's corner-specific height.
Before reading that I thought I plunger values were the more important and that the calibration correlated plunger values with ride height sensor voltages.
Now I will have to experiment more. (Automotive AI results are often wrong.)
Crazy complicated and often frustrating system.
Member
Joined: Feb 2018
Posts: 227
Likes: 55
CL500, W212 e350 mega-spec
That's why someone made and sells these: https://www.ebay.co.uk/itm/122650520545
So these will be ideal to take down the slightly higher corner and tweak all the rest.
So these will be ideal to take down the slightly higher corner and tweak all the rest.
Senior Member
Joined: Mar 2023
Posts: 282
Likes: 88
C230K
That's why someone made and sells these: https://www.ebay.co.uk/itm/122650520545
So these will be ideal to take down the slightly higher corner and tweak all the rest.
So these will be ideal to take down the slightly higher corner and tweak all the rest.
Member
Joined: Feb 2018
Posts: 227
Likes: 55
CL500, W212 e350 mega-spec
I think the original idea is that you can "SLAM" your Merc with a kit like this... but for someone who isn't interested in that sort of thing it should work just as well for tuning the ride height to level it all out.
Member
Joined: May 2020
Posts: 247
Likes: 57
From: Fort Worth
2005 CL55 AMG || 2005 CL65 AMG || 1989 560SEC
I think if I can remember as far back as yesterday when I was looking at this that the plunger levels look even all around. I imagine the reason I've got odd ride heights is just down to condition of the sensors and arms etc. 3 corners are close enough and one corner sits a bit higher than it should but hasn't maxed out or anything like that. The corner which is too high had the strut replaced although I seem to remember it always looked a little ungainly on that corner forever. I just never thought about adjusting it until recently. I think I'm going to get the adjustable link arms and do it like that, should be easy then.
Also had another similar episode caused by one of the acceleration/inertia sensors going bad- they're located by the strut towers on my CL. Not sure if there are 2 or 4.
