ABC - Active Body Control Drive Carefully
Senior Member
Joined: Mar 2011
Posts: 277
Likes: 0
From: Nebraska
2005 CLK500 cab, 2004 S600 designo mocha
As a Master Certified factory trained tech who was assigned 'troubleshooting' at the dealer where i worked from 2000-08 i saw my share of 'unfixable' ABC problems..at first when i went thru the 'guided tests ' in the DAS program we used..if it said 'radial piston pump is defective' i replaced it..But after doing probably over 100 if them with mostly negative results overall.. i began to start thinking..hey ..maybe the pump WASNT REALLY BAD?..after all its simply a power steering pump just piggybacked off of.. a powersteering pump !!..and when i thought about it .. over the 40 yrs ive been working on cars..and airplanes (FAA powerplant cert) i can count one ONE HAND how many power steering pumps ive replaced that were actually NOT PUMPING (and still have 4 fingers left over).the bottom line here is the techs at the dealers are nothing but parts changers .. espcially when told BY A COMPUTER to change the part..The mb DAS program used to diagnose mb vehicles.. like ANY diagnostic program .. should NOT be assumed 100% correct 100% of the time..especially with the 'low system pressure' DTC !! I drive a 95 124 coupe AND a 03 SL55..so when i found that same fault code in my own car im NOT going to replace a pump that isnt broken in half melted into one glob.. plain and simple.. so i took the time to find out the REAL source of the low preesure DTC.. (to be continued)
I'm not trying to be too skeptical, but I don't really believe the claims you make. You say the ABC pump is power steering pump piggybacking off a power steering pump? It's just one unit, one pump.
Also, you claim it's practically the same as any other power steering pump. A normal power steering pump runs around 500psi-800psi. This Mercedes pump runs 3,000psi. That's nowhere close to the same.
Another claim you make is that the pump isn't the cause of the ABC failures. Why is it that people's ABC problems are fixed after replacing the pump?
Junior Member
Joined: Feb 2013
Posts: 31
Likes: 1
From: Bible Belt
124.052 230.374
I never said the ABC pump and the power steering pump were one pump. they are 2 separate pumps in one housing sharing the same driveshaft..thats why the unit is called a TANDEM pump..just because the ABC pump runs at high pressures doesnt mean itsa tottaly different animal.The reason that ABC pump replacement cures alot of problems is (INMHO)that the device called the Suction Throttle Valve comes with a new pump.its an electrically operated valeve located on the outside of the pump.The ABC system is unforgiving of Lack of Periodic Maintenence (fluid changes) the fluid gets worked pretty hard even driving mellow.The Pentosin CH11 is simply a synthetic hydralic fluid withan UNUSUALLY high combustion temperature .so its loaded down with fire retardant additives that precipitate out after being heated (over 200degrees F) and cooled a few hubdred times.. Almost every case of ABC problems can be traced to old fluid.
Senior Member
Joined: Mar 2011
Posts: 277
Likes: 0
From: Nebraska
2005 CLK500 cab, 2004 S600 designo mocha
So can the Suction Throttle Valve be accessed or replaced reasonably? It seems MANY users experience failure around 65k-70k miles. Any idea of a more specific period that the fluid should be changed?
I assume you're already working on completely taking apart the ABC pump and repairing the Valve? Pics would be great.
I assume you're already working on completely taking apart the ABC pump and repairing the Valve? Pics would be great.
Senior Member
Joined: Feb 2003
Posts: 443
Likes: 118
'03 S55 (79K miles)
Waiting to hear more, mbcoupe57...Suction Throttle Valve?
Is it serviceable?
i did a turkey-baster fluid replacement at the reservoir last year and I hope i have extended the life of my ABC. If I can get away with simple changes of fluids and filters, I would be happy. My friend just sold his '03 S55 because the ABC replacement set him back many $thousands and he was fed up.
One good thing about a forum is you can come back to it 4 years after your original posts and see if maybe somebody has a better idea for a fix.
i did a turkey-baster fluid replacement at the reservoir last year and I hope i have extended the life of my ABC. If I can get away with simple changes of fluids and filters, I would be happy. My friend just sold his '03 S55 because the ABC replacement set him back many $thousands and he was fed up.
One good thing about a forum is you can come back to it 4 years after your original posts and see if maybe somebody has a better idea for a fix.
Junior Member
Joined: Feb 2013
Posts: 31
Likes: 1
From: Bible Belt
124.052 230.374
i dont know ive only had to clean them.. im gonna loo into it..there are bleeders in each wheelwell for each wheel just follow the piping there are not easy to see but they are there.. since the shocks have no return system THAT fluiD would help if it was replaced so what i during the ABC service is while car is stopped with key on engijne off front wheels pointed dead ahead i reach around open bleeders usually both on either fron or back andlet the shock collapse with forces most of the old fluid out the bleeder.. the start car and play with the height buttoncycle from lo to max height QUICKLY while car is running to raise it back up The abc sys will default within5 secs if it doesnt detect car movement when switched.. i cycle the key to reset red warning message the try again.. some pumps will cavitate especially when the STV has been removed to clean. i gtab my blow gun and aquirt some air in the dipstick hole and pressurize the resevoir that always works
Newbie
Joined: Jun 2011
Posts: 1
Likes: 0
BMW 328Ci
Hello all,
I'm in this pickle as well now. Red sign of ABC-Death has struck my SL. The bleed marks on the drive still hurt me when I look at them :-(
No idea where to start and what to do... do I trust the 'so called professionals' at MB Dealership or what other option do I have?
Everything on the car has always been MB Dealership and I've maintained that since I bought it almost two years ago.
The stress of it all is too much, but I have to admit driving it on a nice sunny day takes it all away instantly :-)
I look forward to any suggestions or recommendations.
I'm in this pickle as well now. Red sign of ABC-Death has struck my SL. The bleed marks on the drive still hurt me when I look at them :-(
No idea where to start and what to do... do I trust the 'so called professionals' at MB Dealership or what other option do I have?
Everything on the car has always been MB Dealership and I've maintained that since I bought it almost two years ago.
The stress of it all is too much, but I have to admit driving it on a nice sunny day takes it all away instantly :-)
I look forward to any suggestions or recommendations.
Junior Member
Joined: Apr 2009
Posts: 59
Likes: 0
From: seattle, wa
07 E63
suction valve
so I have posted this Q on different thread but no one got back. Here is the picture of the suction valve, and I'm wondering if that little hole should be there or it did not retract back completely? I just assume. because I think it allows the pressure to go back into the fluid tank, and that's why the pressure is not built from the pump into the farther ABC system.
thanks
here is the link : https://mbworld.org/forums/mercedes-...build-kit.html
thanks
here is the link : https://mbworld.org/forums/mercedes-...build-kit.html
Newbie
Joined: Jul 2013
Posts: 2
Likes: 0
2003 S55 AMG
2004 S55 AMG same ABC problem
Started at 67000 miles. There was a recall on the pressure hose. Got that replaced. 75000 got the ABC pump replaced. 94000 there was ABC leak, again changed hydraulic oil, valve... 103000 again pump, oil, seal... It was all done at the authorized Mercedes Benz dealership service. Currently, at 114000 when parked the car leans to one side and to level, I need to press the button. My tires got worn out. I just don't want to go back to the same service.
Any suggestions for a good mechanic in the Dallas area?
Any suggestions for a good mechanic in the Dallas area?
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Newbie
Joined: Jul 2013
Posts: 2
Likes: 0
2003 S55 AMG
2004 S55 AMG same ABC problem
Started at 67000 miles. There was a recall on the pressure hose. Got that replaced. 75000 got the ABC pump replaced. 94000 there was ABC leak, again changed hydraulic oil, valve... 103000 again pump, oil, seal... It was all done at the authorized Mercedes Benz dealership service. Currently, at 114000 when parked the car leans to one side and to level, I need to press the button. My tires got worn out. I just don't want to go back to the same service.
Any suggestions for a good mechanic in the Dallas area?
Started at 67000 miles. There was a recall on the pressure hose. Got that replaced. 75000 got the ABC pump replaced. 94000 there was ABC leak, again changed hydraulic oil, valve... 103000 again pump, oil, seal... It was all done at the authorized Mercedes Benz dealership service. Currently, at 114000 when parked the car leans to one side and to level, I need to press the button. My tires got worn out. I just don't want to go back to the same service.
Any suggestions for a good mechanic in the Dallas area?
Newbie
Joined: Sep 2015
Posts: 1
Likes: 0
2001Mercedes-Benz cl600
Oil leaking under the passengers side after adding ABC oil
Yeah you need a new or an excellent rebuilt pump.
Once I had a leak but was underneath the car by the transmission (not the motor area), there is a sensor and rubber O-ring in that location. Surprisingly it dumped a lot of fluid overnight but once I changed the O-ring the leak stoped and I had no issue until 15k miles later when the pump leaked from its front seal and needed to be replaced.
Please specify where its leaking from.
Thanks!
Once I had a leak but was underneath the car by the transmission (not the motor area), there is a sensor and rubber O-ring in that location. Surprisingly it dumped a lot of fluid overnight but once I changed the O-ring the leak stoped and I had no issue until 15k miles later when the pump leaked from its front seal and needed to be replaced.
Please specify where its leaking from.
Thanks!
Junior Member
Joined: Feb 2013
Posts: 31
Likes: 1
From: Bible Belt
124.052 230.374
its the fluid
The ABC fluid breaks down fairly quickly because of the high heat involved in operation . The fluid is a compromise as it is nearly 100% NON FLAMMABLE. ! Consider what would happen if conventional (syn or not) fluid was used and a leak developed on a system with over 2000 psi .spraying onto a Ct converter. I have used my own blend of fluid in my car with lucas trans or power steering treatment. But Thats my own car (03SL55) which i have owned for 10 yrs. The valves that cause sag when stopped are cleanable even tho not avaialble separately. The metering vales although removable cannot ve easily cleaned save for some zylene soaking the the spool only and patiently working it loose again.. Im a Master cert MB tech but on my car im not replacing anything unless its broke in more than 2 pieces LOL
Junior Member
Joined: Feb 2013
Posts: 31
Likes: 1
From: Bible Belt
124.052 230.374
I just blew one more strut last week. Repair bill came to $4500, I had to pay $2500. The strut ran me $1300. Warranty company did not cover struts per their agreement. They did pay for some hoses and stuff which was around $600.
I think Mercedes is overcharging for the strut. It may be a complex part but since they fail often enough I think they should reduce the price.
I think Mercedes is overcharging for the strut. It may be a complex part but since they fail often enough I think they should reduce the price.
MBWorld Fanatic!
Joined: Apr 2009
Posts: 1,264
Likes: 366
'06 MB S55 AMG; '04 Audi Allroad 4.2; '05 BMW M3 Conv.; '92 MB 500E
I never said the ABC pump and the power steering pump were one pump. they are 2 separate pumps in one housing sharing the same driveshaft..thats why the unit is called a TANDEM pump..just because the ABC pump runs at high pressures doesnt mean itsa tottaly different animal.The reason that ABC pump replacement cures alot of problems is (INMHO)that the device called the Suction Throttle Valve comes with a new pump.its an electrically operated valeve located on the outside of the pump.The ABC system is unforgiving of Lack of Periodic Maintenence (fluid changes) the fluid gets worked pretty hard even driving mellow.The Pentosin CH11 is simply a synthetic hydralic fluid withan UNUSUALLY high combustion temperature .so its loaded down with fire retardant additives that precipitate out after being heated (over 200degrees F) and cooled a few hubdred times.. Almost every case of ABC problems can be traced to old fluid.
But I am trying to confirm if it's good old Pentosin CHF 11. If so, has anyone come up with any better hydraulic fluid? Pentosin is really old stuff, and fluid technology has come a long way since then. Or has it? It looks like only Pentosin and Fuchs carry the MB 344.0 spec approval. Any thoughts?
Cheers,
maw
Last edited by maw1124; Sep 16, 2015 at 10:05 PM.
Junior Member
Joined: Feb 2013
Posts: 31
Likes: 1
From: Bible Belt
124.052 230.374
i think its the chf 11s.. the green stuff.. i change mine at 30K... i use mobil 1 syn atf with lucas trans additive but for liability reasons i cant reccommend this to anybody since the risk of fire if a leak develops at the wrong spot ( onto the cat conv)... im just sayin what i use in my 03SL55 
MBWorld Fanatic!
Joined: Apr 2009
Posts: 1,264
Likes: 366
'06 MB S55 AMG; '04 Audi Allroad 4.2; '05 BMW M3 Conv.; '92 MB 500E
i think its the chf 11s.. the green stuff.. i change mine at 30K... i use mobil 1 syn atf with lucas trans additive but for liability reasons i cant reccommend this to anybody since the risk of fire if a leak develops at the wrong spot ( onto the cat conv)... im just sayin what i use in my 03SL55
Cheers,
maw
MBWorld Fanatic!
Joined: Apr 2009
Posts: 1,264
Likes: 366
'06 MB S55 AMG; '04 Audi Allroad 4.2; '05 BMW M3 Conv.; '92 MB 500E
Is this for better heat resistance, since the Pentosin is only good to 275 deg F? If so, why not the Mobil Jet Oil from the supercharger? Too thick?
Ever considered this?... http://www.amsoil.com/shop/by-produc...?code=AWI05-EA. It doesn't pour as cold, but it's better on the high end. Unless your car sits outside in Alaska, I'm not sure why you would care about a colder pour point.
maw
Ever considered this?... http://www.amsoil.com/shop/by-produc...?code=AWI05-EA. It doesn't pour as cold, but it's better on the high end. Unless your car sits outside in Alaska, I'm not sure why you would care about a colder pour point.
maw
Last edited by maw1124; Sep 19, 2015 at 03:02 PM.
Junior Member
Joined: Dec 2013
Posts: 36
Likes: 4
From: San Jose Bay Area in California
2016 Mercedes Benz GL550
http://www.amazon.com/gp/aw/ol/B00JMAPUAO/ref=mw_dp_olp?ie=UTF8&condition=new
Last edited by gregwang168; Sep 19, 2015 at 06:40 PM. Reason: Wrong link
Junior Member
Joined: Sep 2014
Posts: 21
Likes: 3
.
do the conversion ditch the ABC altogether its useless.
http://www.benzworld.org/forums/w220...rsion-abc.html
strut masters makes a kit that will get rid of this issue all together.
http://www.benzworld.org/forums/w220...rsion-abc.html
strut masters makes a kit that will get rid of this issue all together.
Senior Member
Joined: Feb 2003
Posts: 443
Likes: 118
'03 S55 (79K miles)
The spec says to use Pentosin CHF 11S. Don't use CH11.
CHF 11S seems to be getting more plentiful and easier to find, both in Pentosin brand and others. It is used in Audi and BMW power steering systems.
Good luck to all who try other fluids. Viscosity of the oil is certainly figured into the design of the valves so I wouldn't mess with other oils. Your mileage may vary, but hopefully your mechanic skills and wallets outweigh the risks for you.
CHF 11S seems to be getting more plentiful and easier to find, both in Pentosin brand and others. It is used in Audi and BMW power steering systems.
Good luck to all who try other fluids. Viscosity of the oil is certainly figured into the design of the valves so I wouldn't mess with other oils. Your mileage may vary, but hopefully your mechanic skills and wallets outweigh the risks for you.
MBWorld Fanatic!
Joined: Nov 2010
Posts: 2,605
Likes: 343
From: Welwyn, Herts, UK
2006 S600
do the conversion ditch the ABC altogether its useless.
http://www.benzworld.org/forums/w220...rsion-abc.html
strut masters makes a kit that will get rid of this issue all together.
http://www.benzworld.org/forums/w220...rsion-abc.html
strut masters makes a kit that will get rid of this issue all together.
Nick
