PUMP Noise
 

2001 - S500

Can anyone tell me if the Power Steering Pump and the ABC Pump are one and the same? Meaning if I have to purchase a power steering pump I can also refer to it as an ABC pump (same part number). I had a moaing noise coming from the front driver side whenever I accelerated on the gas and it produced no warning messages, but now the moaning noise is coming and going. When I hear the noise there's no message, but when the noise disappears I get a warning message "Active Body Control - Please Drive Carefully" there are no leaks, cars has not dropped, but I can't raise the car with the Level Control Button when there is NO noise, but when I hear the noise I can raise the car using the button. I think the pump stops working when there is no noise. My non-mercedes extended warranty company "Great Lakes" covers a P/S Pump, but I dont see anything about a ABC Pump. Are they the same pump???

Thanks

Yes, that is the same pump.

However..most of the "droning" noises on that system are from a BAD system accumulator..MB issued a bulletin on that noise 16 March 2005. Bulletin # P-B-32.50/24

Where can I get this Bulletin?

From a dealer OR I can e-mail that to you.

Thanks.. email to didonato@nosc.mil

I got a different answer on another fourm. It says that its not one pump. see below:

Absolutely not...
Actually there isn't a pump for ABC, there is the Air -matic pump that control your ABC and it is a pneumatic pump not a hydraulic pump like your P/S.

Stay away from that forum....Air matic is a completely different suspension system.

It uses an air pump & air shocks...ABC is hydraulic.

Both are available on the W220 S500 chassis....