Hi all, I am about to replace the two rear level sensors on my 2006 W221 S600 as part of chasing an ABC error and any additional info would be helpful.
The reason is I have been having some odd ABC behaviour and a random ABC error - yellow. It clears on a car restart but logs a pressure error on the rear left when the Star is checked. Now this is where things get peculiar. I can hear a noise that sounds like its coming from the rear left but hard to tell. Its a very faint knocking type noise and can be heard at 5mph on perfectly flat surface and also when the car is stopped but running. I have it recorded so will try and share some links if I can.
ABC History in my ownership:
All seemed to be working OK but blew the high pressure hose from the pump after Christmas.
Replaced with an OEM used one.
System flushed, new filter installed and new fluid.
Rodeo and tested - pressures all good.
Car running and driving fine - no problems aside from a not about teh level sensors being a bit of a DIY job.
Car went for NCT test and visual fail for broken spring and rear left strut. It actually passed all teh vibration and balance tests but they say a bulge in teh gaitor and went poking and managed to get the break to come through.
Two rear rebuilt struts ordered, decided to replace both rears at teh same time. Qiality looked excellent and in as new condition.
Struts fitted by a garage that specialise in merc.
More fluid, rodeo and testing.
Car seemed fine.
Week or so later the faint knocking and an ABC error.
Error cleared - error returned.
Back to garage - only thing they seen similar once was an air lock.
More rodeo and bleeding.
Noise stopped
Returned a few days later and ABC error.
Error cleared - car back in for its national car test and passed with flymg colours.
ABC error and knocking still persist.
Now have parts to start isolating and try and get to the bottom of it,
On one recent fault code after I took a 90 degree left into the estate where I work at around 15mph I decided to not turn the car off but investigate. I reveresed the car in the warehouse and the left rear strut was fully extended. It was much higher than the "raise height" position. Raising or lowering the car did alter the level of the other three struts but not the RL. I hooked up the star and pressure error was present "Signal Implausible" Code 520A. Rear left showed 2.33V so within spec.
I did not clear any errors but put car in rodeo mode for a few seconds. All other struts did their thing but rear left did not move so I stopped it. All this time the rear left is still fully extended. I now belive this may be a fail safe setting wwhere the ABC fully extends to protect itself but have nothing to support that only some random internet reading. At this point I decided to clear the codes with the Star. As soon as I did that the strut sat back down as normal. I did not cycle the car ignition at that point so the car had been running continuously. After the strut reset I did clear the error. So basically - the car has been parked since waiting for the parts.
I drove it the last two days to verify the issue is still there and it is. I still have a mouse gently tapping with a hammer and did get an ABC fault. I have't pulled the code yet but suspect it will be what I expect
The current level sensors have been tweaked / modded lets say with one home made and one welded by the previous owener/s. They seem to work OK but the linkages etc could be binding or sticking. There are two on the rear of the W221 and relatively easy to swap so they will be replaced along with brackets for new Merecedes OEM. For this reason I am looking for the specific shop procedures on a W221 ABC level calibration so that I can be 100% sure that the levelomg sensor system is correct.
Once replaced I will calibrate and see can I recreate the fault.
The next step would be to replace the pressure sensor on the valve block that feeds the left rear strut in case that has a fault and retest. After that then I fear it may be replace the new strut or look at the valve block itself.
I have serached the WIS on my Star but not been able to find teh procedure. I have searched teh forum but not had any luck finding a specific W221 procudure. I did locate AR40.20-P_0301l which details the procedure for the W220 and C215 models so can use that as a reference.
For others that may be doing similar the relevent threads with decent info on teh forim I have found so far are linked below:
2001 CL55
Stock 2001 CL55 ABC level calibration values
2006 W220 S65 - slight differences between Airmatic and ABC discussion
S65: ABC leveling.
Thread on calibrating and storing but not W221 specific.
www.benzworld.org
Link to post with teh W220 / C215 pdf procedure
www.benzworld.org/forums/attachments/w220-s-class/2082873d1486433097-ride-height-specs-check-vehicle-level-front-rear-axle
That;s pretty much all off teh top of my head but any questions , ideas, comments, procedures, divine inspiration, seance etc all welcome. Hopefully I can get to the bottom of it as its really annoying me. I will try and pull together some souind clips and video to share.
The reason is I have been having some odd ABC behaviour and a random ABC error - yellow. It clears on a car restart but logs a pressure error on the rear left when the Star is checked. Now this is where things get peculiar. I can hear a noise that sounds like its coming from the rear left but hard to tell. Its a very faint knocking type noise and can be heard at 5mph on perfectly flat surface and also when the car is stopped but running. I have it recorded so will try and share some links if I can.
ABC History in my ownership:
All seemed to be working OK but blew the high pressure hose from the pump after Christmas.
Replaced with an OEM used one.
System flushed, new filter installed and new fluid.
Rodeo and tested - pressures all good.
Car running and driving fine - no problems aside from a not about teh level sensors being a bit of a DIY job.
Car went for NCT test and visual fail for broken spring and rear left strut. It actually passed all teh vibration and balance tests but they say a bulge in teh gaitor and went poking and managed to get the break to come through.
Two rear rebuilt struts ordered, decided to replace both rears at teh same time. Qiality looked excellent and in as new condition.
Struts fitted by a garage that specialise in merc.
More fluid, rodeo and testing.
Car seemed fine.
Week or so later the faint knocking and an ABC error.
Error cleared - error returned.
Back to garage - only thing they seen similar once was an air lock.
More rodeo and bleeding.
Noise stopped
Returned a few days later and ABC error.
Error cleared - car back in for its national car test and passed with flymg colours.
ABC error and knocking still persist.
Now have parts to start isolating and try and get to the bottom of it,
On one recent fault code after I took a 90 degree left into the estate where I work at around 15mph I decided to not turn the car off but investigate. I reveresed the car in the warehouse and the left rear strut was fully extended. It was much higher than the "raise height" position. Raising or lowering the car did alter the level of the other three struts but not the RL. I hooked up the star and pressure error was present "Signal Implausible" Code 520A. Rear left showed 2.33V so within spec.
I did not clear any errors but put car in rodeo mode for a few seconds. All other struts did their thing but rear left did not move so I stopped it. All this time the rear left is still fully extended. I now belive this may be a fail safe setting wwhere the ABC fully extends to protect itself but have nothing to support that only some random internet reading. At this point I decided to clear the codes with the Star. As soon as I did that the strut sat back down as normal. I did not cycle the car ignition at that point so the car had been running continuously. After the strut reset I did clear the error. So basically - the car has been parked since waiting for the parts.
I drove it the last two days to verify the issue is still there and it is. I still have a mouse gently tapping with a hammer and did get an ABC fault. I have't pulled the code yet but suspect it will be what I expect
The current level sensors have been tweaked / modded lets say with one home made and one welded by the previous owener/s. They seem to work OK but the linkages etc could be binding or sticking. There are two on the rear of the W221 and relatively easy to swap so they will be replaced along with brackets for new Merecedes OEM. For this reason I am looking for the specific shop procedures on a W221 ABC level calibration so that I can be 100% sure that the levelomg sensor system is correct.
Once replaced I will calibrate and see can I recreate the fault.
The next step would be to replace the pressure sensor on the valve block that feeds the left rear strut in case that has a fault and retest. After that then I fear it may be replace the new strut or look at the valve block itself.
I have serached the WIS on my Star but not been able to find teh procedure. I have searched teh forum but not had any luck finding a specific W221 procudure. I did locate AR40.20-P_0301l which details the procedure for the W220 and C215 models so can use that as a reference.
For others that may be doing similar the relevent threads with decent info on teh forim I have found so far are linked below:
2001 CL55
Stock 2001 CL55 ABC level calibration values
2006 W220 S65 - slight differences between Airmatic and ABC discussion
S65: ABC leveling.
Thread on calibrating and storing but not W221 specific.
Adjusting and Storing AIRmatic Levels
Having spent hours adjusting my AIRmatic height levels using SDS, only to find that after a couple of days they were back to where they were before I started, ie the car with a slight lean, I came across a posting by MB World Fanatic aleksandar1099 as to why. And note, if the AIRmatic does not...
www.benzworld.org
Link to post with teh W220 / C215 pdf procedure
www.benzworld.org/forums/attachments/w220-s-class/2082873d1486433097-ride-height-specs-check-vehicle-level-front-rear-axle
That;s pretty much all off teh top of my head but any questions , ideas, comments, procedures, divine inspiration, seance etc all welcome. Hopefully I can get to the bottom of it as its really annoying me. I will try and pull together some souind clips and video to share.
