David Alvey

Been reading the forums for a little while but a first time poster. I have a 2003 S55 and love the car. For the last couple of years I have been having sudden drops of the right rear when parked for any length of time. I had theABCpumpfail3 yrs ago and had it replaced. At that time I asked the shop what to do about the suspension drop and they said don’t worry about it until it gets worse. Not my idea of a fix but didn’t know as much about the system or that one could rebuild the valve blocks then. Recently had the ABC burp experience and decided to go through the system replacing all wear items. I changed all 4 accumulators (found 3 bad), changed the left rear strut and rebuilt the value blocks with new seals. Put it all back together with fresh Pentosin and I think I may have fried the ABC pump as I didn't know to pre-pressurize the system before starting (how do you do that?) It took several attempts of starting the car, pressing the height adjustment button and shutting off the engine with each Red Error msg then restarting. After several attempts the red ABC failure message went away and all seemed to work fine. The left side of the car is 1.5" higher than the right. My reading says this is a calibration that requires a STAR system (don’t have one) to fix. I also drove the car a few miles and after 10 minutes or so I get the white ABC error message but it still seems to work. I also noticed when I stop the car the front end starts rising – never did this before the work.

I took it to a local Euro repair place that has a STAR system to rodeo the car, thinking a good purge of any air in the system might be the cure. They are telling me they got 3 pages of fault codes, then cleared them - all is fine, then get 3 more pages of fault codes again. They are suggesting the ABC control module needs replacing. Reading some posts here about the front-end drop, I have ordered 2 new accelerometer sensors hoping that may cure the ABC issue. How do you know when the ABC control module is bad and IF I purchase a salvage ABC control module of the same part number, will there be any coding required?

Astro14

You're just guessing at this point. Red error message means a serious fault, like low pressure, or the car sitting too low.

You have no idea what the pump output pressure is right now, and no idea what the 8 sensors for ride height (one in each strut, one on each control arm) are seeing for values.

Maybe it's a bad module - very likely, it's not. I'm not arguing that the 3 pages of codes are OK, they're not, but until you:

1. Know what each code says and
2. follow the troubleshooting steps in SDS for each code

You're really just guessing. Sounds like your mechanic is guessing, too....

David Alvey

The repair place just got their star system and did say they were waiting on complete training. They are recommending to take the car to the dealer. I will be picking up the car tomorrow and will request the 3 pages of faults. What is weird is the mechanic said they would clear and then come back again, thus the recommendation of changing the control module.

S430AMG

If I had ABC and the car was in great shape I would simply go to spring/shock set upon the 1st sign of any ABC troubles.

Astro14

You might go to springs/shocks at the first sign of trouble - but I wouldn't.

ABC is part of what makes the S-class unique. I've never had such a combination of smooth ride and awesome handling. Your Spring/Shock set up simply can't match that. Just not the same. ABC uses multiple sensors (yaw, pitch, strut height, ride height, etc.) to adjust the suspension, keeping the car flat in turns, really flat, in a way that springs, even with huge roll bars, can't match. ABC prevents squat on acceleration, and dive on braking. And while it's doing all that, there are no roll bars to compromise the ability of one wheel to respond to a bump. I've had cars with big roll bars - great in turns, but they compromise independent suspension articulation when one wheel encounters a big bump. ABC gives you full articulation, while keeping the roll resistance. No compromises. It just performs better.

I've just done a flush on my ABC. System still works perfectly.
Now, I've done a couple of hoses, one of which required dropping the rear sub-frame, and I've replaced all 4 accumulators and rebuilt the valve blocks. But I've still spent less than a spring/shock set up and I've still got the full performance capability of the car.

knowbenz

If you can post the current fault codes it will help in trying to figure out the problem. wires switched around on the valve blocks could cause problems. Likely something in common for all the codes to keep coming back.

David Alvey

Found the problem to all my ABC woes today. As mentioned in the original post, I drained the old oil, removed and rebuilt both valve bodies and replaced a leaking strut. When I put everything back together the right side of the car sat apx 1.5 inches lower than the left and I was getting all kinds of screen errors. I spent a few hours tracing down each wire connector to the front and rear valve blocks. I needed to make sure each wire was plugged into to the correct valve as some of the colored dots matching the plugs were lost to cleaning solvent during the seal replacement process. They were all in the correct valves so no problem there but while under the car I immediately realized the issue. The error messages, fault codes, white screen and red screen were all the result of the left rear A arm sensor (sensor and rod) being re-mounted incorrectly on the replacement of the strut. It was apx 45 degrees inverted. Remounted it correctly and walla,,,! No more error messages. I’m very surprised one sensor can cause so much havoc on this system but obviously the ABC system was not happy with my work but all is well as we have now made up. I love my ABC system again.

Thanks for for all the feedback and suggestions.

BrentWa

David, love your post about the 03 AMG but how could u tell if the rear A arm sensor was backwards? Was it the prior shop that changed it or yourself?? U got lucky as a dealer would have thrown out everything and start from scratch costing another $3K

BrentWa

How's your S600 running? I also have an '05.

jsh0ffman

I have an 03 SL55AMG and recently while driving the left side will drop all the way down to the axel. Then I hit the hydraulic lift button and it comes back to level again. However I start driving again and the front will slowly drop down to the axel in only about 500 yards. I had the problem originally when the battery in the trunk wore out and the right side of the car dropped. I replaced the trunk battery, started the car and immediately after starting the car, the suspension popped back into level position again. The car drove ok for about two weeks and then the problem returned. I took it to the MBZ dealer and they replaced the seals in the suspension, drained and flushed the fluid and called me to come pick up the car ($3k). I jumped into the car, and as soon as I inserted the key into the ignition, the red ABC light came on. The dealer said it was an intermittent light failure and to just drive it. I got three miles down the road and the front end completely dropped out again. I had it towed back to the same MBZ dealer in Carlsbad, Ca and they took it back for further analysis. They called a few days later and said it might be the ABC Control Unit ($2k) so they are replacing that as well. If this doesn't work are there any guesses as to what might be best to look at next? The accumulators, sensors, hoses? Looking for advice, thanks.

wallyp

Any COMPETENT dealer (or independent shop) would put the car on SDS (STAR Diagnostic System), which would tell them immediately what was wrong with the car, and how to fix it.

knowbenz

These kinds of comments is what devalues good technicians. Customers google issues and are put under the impression that the computer tells you what is wrong with the car. This however is not true at all. You need to be able to interpret the fault codes and have a develop a diagnostic path to determine what is wrong with the car. If it were as easy as plugging in a computer then we could just pay C level techs to diagnose the problems

wallyp

"I took it to the MBZ dealer and they replaced the seals in the suspension, drained and flushed the fluid and called me to come pick up the car ($3k). I jumped into the car, and as soon as I inserted the key into the ignition, the red ABC light came on. The dealer said it was an intermittent light failure and to just drive it. I got three miles down the road and the front end completely dropped out again. I had it towed back to the same MBZ dealer in Carlsbad, Ca and they took it back for further analysis. They called a few days later and said it might be the ABC Control Unit ($2k) so they are replacing that as well."

Good technicians?

I stand by my statement.

ItalianJoe1

There are bad techs in any industry, and because most customers don't want to spend money on ABC cars, not many of them come in to the dealership. I was more familiar with ABC because I already owned a CL before I started working at MB, than most of the people who had been there for a decade or more.

But, especially with this system and these cars, diagnosis is KEY. The computer does not tell you what is bad (dozens of pumps have been replaced for a 'low pressure' code that is almost never the pump), but you have to be able to see the data the car sees and diagnose the fault. Guessing and throwing parts at it will be very expensive and is never fun for the tech or customer.

knowbenz

He said he took it to the dealer. You don't think they hooked it up to their SDS? Thats likely the first thing they did and if it worked the way you want to say it does they would have had the answer. My comment has nothing to do with the other guys visit to the dealer. It has to do with people making comments that suggest the computer scan tells you what is wrong with it.