sam12

Hi,

I have access to the Mercedes Electronic Parts Catalog (EPC) and Work Instructions (WIS). However I don't have access to the technical service bulletins.

I have a pdf copy of this document, however I don't have the attachments, images and sound files, does anyone have access to this? I have this strange 'honking' noise which has been asked about a few times on this forum by owners with ABC, however nobody has solved. I am 95% this document is the same problem I am facing and im trying to judge if I can do it DIY. Part is £100 or so.

Document number is Ll32.50-P-056781

https://static.nhtsa.gov/odi/tsbs/20...62829-2280.pdf

crconsulting

This below, would be an easy diagnostic procedure to perform with no cost in parts...
If your noise goes away, that is the problem....
from PDF:


Remedy:
Note: The ABC system can be switched to a passive state by unplugging a connector to an acceleration sensor
(B24/3, B24/4 or B24/5). The noises described above should now no longer occur. If noises continue to occur, they
are not attributable to the ABC system.

Also note that the pulsation damper is a common failure point in R231 ABC system.

Good Luck!

sam12

So i have disconnected the acceleration sensor on one of the strut towers and it appeared to go away, hard to tell as noise might only happen once every 10 mins. Very strange driving the car with ABC deactivated! Makes you realise how good it is!

Pump and pulsation damper already done under warranty with previous owner.

I can understand how you clamp off the return to the reservoir as its a soft pipe, however pump to valve block must be super reinforced, so no idea how you are supposed to clamp that, hence i want to see the images to see where/how to clamp

sam12

Update: I had the return valve replaced in my front ABC valve block and this has cured the honking noise once the ABC oil is warm.