S-430 ABC, Active Body Control
Every morning when I first start the car, after 10 seconds or so, the red ABC warning comes up. Then, usually but not always, within a minute, the red warning disappears and the car rides normally and the level is ok. However, if I then turn off the motor, when I restart it the red ABC warning comes on, and the car rides very badly. After the second start, I can't get rid of the red ABC warning.
I took it to the MB dealer who said there is a leak in the hydraulic pump, but that makes no sense. I haven't refilled the hydraulic oil in over a year, there's no sign of oil leaks on my garage floor, and if the problem was low hydraulic fluid, why does the car "cure" itself after a minute and ride ok.
The MB dealer estimates $4000 to replace the pump, but they can't or won't guarantee that will fix the problem. I would REALLY appreciate any suggestions.
If there is a leak, shouldn't it be low? can you check the levels in ABC and see where they are at when you first start, then again after 2nd start?
Well from what you have described I would also say your ABC pump is on it's way out. My S55 acted very similar a few years ago. On a cold start the car would be fine but a warm start the ABC pump was dead. Well what happened was simply that the warmed up fluid and pump just couldn't build up the pressure the ABC system requires. It then will go into a lock down mode so you can maintain your wheel height as is. The only issue with that is that the ride quality stinks to say the least but you can get home.
Good luck
Johan
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Thanks for your reply. What you say makes sense, so I guess I either need to find an aftermarket/ebay replacement pump, or I'm stuck with a $4000 bill for a 13 year old, but nice, car. Any chance of just replacing the impeller in the pump?
Richard
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Any chance that I can get by with just replacing the impeller? Hope springs eternal.
Of course a junkyard unit is the cheapest option
Personally I'd just keep drivin. Might get 30,000 more miles out of it . I think the tech means it has a pressure leak , not a fluid leak. The pump is leaking internally and can't build pressure as designed
I am STILL at a loss to understand why 3 separate MB repair shops (1 dealer and 2 indies) booked it out as a job that requires 12 hours of labor.
I found the part NIB online for ~$1K (been a while and don't recall exactly but it was a shop out of San Diego, CA) when the dealer and indies all wanted $1700. Going used is high risk and if you are going to invest the time and effort to complete the task yourself you may as well go new. AND I did it without any special tools or knowledge. You would THINK the shops should be able to do it in half that time, right? It can be done. I have a few points of advice though. First, make sure the car is completely supported on blocks with the suspension and tires hanging free. Also the car should not be run for a few days before pulling and disassembling the system. This releases most of the incredibly high pressures in the ABC system. Second, remove the engine cooling fan and radiator to gain more room to work. I did this on a V12TT and you will certainly have much more room to work in but it will help to have the extra room even on the 430. Last, make sure you refill the reservoirs/pump under pressure. You do NOT want to fire up the engine with air in the system. Air hitting the impellers will surely lead to a very short-lived new pump.

Good luck.

If you plan to keep your car for awhile then coilovers could be a good solution to a potentially ongoing problem with the ABC components failing one by one. Installing a different pump may just buy you some time before something else in the circuit fails.
You don't want to get too "upside down" invested in your car.











