nm4ever

My 2001 S55 AMG has started showing warnings that says ACTIVE BODY CONTROL drive carefully and sometimes it says See Workshop. I took it to my mechanic and he says that the Hydrolic pump needs to be replaced. The cost is too high and I am not sure if that will fix the problem.

Has anyone else had this problem? Any advise is greatly appreciated.

whoover

It's probably correct. I would make sure a Mercedes dealer diagnoses it as the ABC takes very specialized expertise. But if the pump is bad it has to be replaced or the car will not be fit to drive.

sound 8

Hi, had exactly the same problem with my S600. Check your ABC reservoir
to see if it needs topping up. Mine did, but then they found a leak but I
carried on topping it up. I was warned by a member to get the leak fixed as it would damage the pump. Eventually I paid $2000 to have new pipes fixed, but with the full pressure the pump started making noises, this was replaced
at half cost. This ABC suspension seems to go wrong alot when you look at this forum.

nm4ever

Hi and many thanks for the tip. Could you (or anyone who knows) also help me with
1- the location of the reservoir (any pointer that can help me identify it),
2- what kind of oil to add, (any specific liquid?)
3- and if it has lost the reservoir liquid, why don't I see any leaks?

Appreciate it!

whoover

You REALLY should think twice about messing with your ABC. For instance, a microscopically small piece of grit introduced into the oil reservoir can cause problems. But if you must:

The reservoir is in the front left (driver's side) area of the engine compartment. It is marked ABC or Active Body Control and OEL. It takes a special Pentosin hydraulic fluid.
It would be very foolhardy to use any fluid you didn't get at the dealer.
I didn't say it's a leak -- you did.

ABC should be serviced now and then. Whatever your problem, you are probably do for a fluid flush and filter replacement. You probably have the old ABC filters, which were upgraded to a more efficient design.

Whether the problem is the pump, a leak, a bad valve block, a bad sensor, a bad strut or a mysterious disappearance of hydraulic fluid is best determined scientifically. If the car were mine and the fluid were low, I wouldn't top it up without finding out why it was low. And because contamination is such a no-no, I wouldn't even open the cap to check the fluid.

IngenereAMG

ABC work is probably best left to an expert.

The problem with these cars as they depreciate, is the ownership experience opens up the opportunity to a new group of people. On the one hand that is great, but on the other hand, the cost of ownership doesn't depreciate. What happens is there are more and more cars out there with deferred and neglected maintenance. I see this with new Ferrari owners, and another car that sticks out is the Porsche 928 that has this happen.

Sometimes, you have to bite the bullet, and this is one of them!

nm4ever

I took my car to the Mercedes authorized service shop, not the dealer, they ran a test and came up with a possible cause and remedy "Component Radial piston pump is defective". Then they said I will need to replace the Hydraulic pump, which will cost me 2150 $$ installed. Should I trust this diagnosis or take it to the dealer for a second opinion? (will definitely add another 250 for the dealer test).

whoover

I would use the dealer. No question. They do more of them, have the right equipment, know the upgrades to make, etc. I'd certainly have them diagnose the problem and see what their price for the fix is.

Hotrod-Realtor

I just went through the same scenario with my S55. The light came on intermittently and then all the time. The dealer (I have the same tech each service) diagnosed it to be the pump. They replaced the pump and flushed and flushed and flushed the system to remove debris from the disintegrated pump that found it's way throughout the hydraulic system. Bottom line was $2,500 and my tech said it may always have problems now depending on where all the crap wound up in the fluid. I have put over 10,000 miles with no issues since then.

Oxygen

That's very unfortunate, I hope it works out for you.

I had a similar situation, except one of my lines blew off off at the crimp and caused damage to the pump because the fluid was gone.

I have a very detailed thread about it here: https://mbworld.org/forums/cl55-amg-...-pictures.html

irieblue

If Mercedes crack shot engineers read this board, maybe they will get a clue and switch to electro magnetic ABC. Hydraulic based ABC is a technology whose time has long passed.. If Boeing can switch from Hydraulic systems to electrics in the 787 Dreamliner, maybe it's time the leading car designers follow suite -- This from someone whose other car is a Lexus Hybrid with Electric power steering, Electric A/C.

nm4ever

I finally took my car to the Mercedes dealer last week and they diagnosed that the reason for the ABC Drive Carefully warning is the EIS control unit and that the ABC fluid must be flushed as part of regular maintenance. They also recommended that I should take care of the leak from transmission and the valve cover gasket totaling 3400 dollars. They said my car should be ready in 2 days. It took them 5 days and finally on Saturday I was called to be informed that while they were flushing the ABC fluid, since the fluid was dirty, it caused the Hydraulic bump to fail and now they will need to replace the pump. Add 2500 dollars to the cost. OMG... I am stunned. To flush the oil, I have to replace the pump? Anyone has seen this before? Did they do something wrong for this to happen? How can I trust them now. What if while replacing the pump, somethings else goes bad? Why did I have to pay for the EIS change to fix the ABC warning? Please advise if anyone can...

Oxygen

That's insane... the pump failed because the fluid was dirty? How dirty could the fluid possibly be and why would the pump not fail earlier?

Hotrod-Realtor

nm,
When my dealer diagnosed the problem, they did so with a hydraulic pressure gauge checking pressures compared to factory specs. In other words before they replaced the faulty pump they checked the system and determined the pump was not putting out enough pressure and must be failing / worn. I do remember the tech being concerned with trash in the system and spent a lot of time flushing everything out after installing the new pump.
If I had to guess I would say that they mis-diagnosed the problem and now realize the error of their ways so they are asking you to pony up extra bucks to cover their ignorance or laziness.
Ask them to reinstall the original EIS control unit after replacing the pump and see if it doesn't work with the "faulty" EIS control unit. Keep in mind you are going to step on some toes asking for this, nobody likes to be second guessed.

I ran into a similar problem with an Impala SS at Randy Marion Chevrolet. My car died doing a burnout one day and after towing it to the dealer they diagnosed it as a fuel pump. I didn't believe them but said go ahead and fix it. They called up a few hours later to report that the fuel pump was not only bad but the distributer was suspect too. I stopped in, questioned the tech and hypothesized he didn't properly check the no start out correctly. He told me he put his ear to the gas tank filler neck and couldn't hear the pump run. I went to the manager and said let's bench test the "faulty" pump. You know it, once we put 12 volts to the pump it started working. I asked for a different tech to work on my car but they refused. I ended up having the car towed to my house where I pulled the front of the engine apart (LT1) and when I got to the distributer I discovered the two screws holding the rotor on had backed out and were laying in the distributer. Two drops of locktite later she purred like a kitten. The dealer did put my "faulty" fuel pump back in allowed me to tow the vehicle to my house and only charge for two tow truck trips. The way I looked at the situation was I saved about $1,000 on repairs that were un-needed.
Best of luck,
Warren

sound 8

I would let a MB dealer to sort out ABC. They have to run a programme when
it's fixed to get it to work properly. Apparently it's like a bucking bronko.

Oxygen

Here's a video of my car doing the rodeo: http://www.youtube.com/watch?v=xkRvV2iWZZw&fmt=18

sound 8

That's probably a lap of the Nuremberg Ring.

jetskilen

Oxygen:
I applaud for your thread and the meticulous content and structure. I am having some difficulty with an 04 sl600 that has a problem with the abc: overnight, the passenger front lowers and it also seems as if the rear passenger possibly dips as well.
The dealer checked it over a one week period and it happened overnight once, thereafter, it was two days before any change.
The problem seems inconsistent and the dealer said it is because the fluid and filter needs to be changed before any further diagnostics can be accomplished to determine if there is a problem with the valves oooh, possible ouch!
What are your thoughts and can you possibly assist in repairs?
It seems as if you are a very competent and professional technician.
please contact me at jetskilen@yahoo.com
thanks so much

Oxygen

jetskilen- thank you!

Regarding your ABC situation.. since the overnight lowering is not consistent, the dealership is right on the money with their diagnosis and solution.

The fluid could be dirty and one of the valves could be getting stuck open and the fluid slowly leaks back into the system when the vehicle is parked. First step to rule out a bad valve block would be to change the ABC filter, check fluid level and run the Rodeo program for 15 minutes. Change the filter again and run the Rodeo for another 15 minutes. Change the filter again and park the car and see what happens. If it stays up you've cleared the valve and you're good to go. If the filters are coming back dark or metalic looking, the pump could be failing and tiny pieces of metal are in the ABC fluid, which would require you to flush out the entire system. If the car continues to sag with new fluid and or after changing the filters several times, I would look into replacing the valve block.

If you are in the New York area I can do all the above for you.

jetskilen

Thank you very much for
Thank you very much for your time in replying to the question: it is obvious that you are an expert in Mercedes.
Do you have a contact number regarding any current and future mechanical servicing?
It is difficult in locating a qualified trustworthy technician.
Look forward in hearing from you.
jetskilen@yahoo.com

abenner5

Just to weigh in here - my S600 is having the exact same ABC problems mentioned earlier.

After the ABC drive carefully light started coming on , I got the fluid flushed & valve block replaced. Was ok for a week, then light started coming on again.

When I brought it in, the pump had failed and was only putting out 5 psi (should be 200 psi, dont quote me if I have these #s wrong).

Strut was also leaking, also a few hoses leaking. Pump, strut and hoses being replaced currently, I should get the car back next week...will let you know how the saga continues!

jetskilen

What is the mileage on your car?

abenner5

68,000 miles.

MR888

Ouch, Stealer strikes again! makes me wonder if I want to move to a 220/215 55/600, my 210 e55 has been quite reliable so far.

djamer

omg, that's crazy man. I reallllly hope you have an extended warranty.. I just got my ABC seviced (flushed) and got a rear body valve replaced (warranty paid). the flush is recommended when you get a Service B done. The flush if done appropriately on schedule should keep ABC trouble free, according to the mb master mechanic i spoke to today.