W140 ABS/ESP Control Unit Fault

[mr_w140]

I have a problem with the brakes on my 1998 Mercedes W140 S500 Saloon. It had been parked for some months and I had been driving it intermittently every few weeks. The last time I took it out for a drive, I noticed that whenever I applied the brakes it would make a metal grinding noise. the pedal also felt very floppy. It definitely was not rust on the discs (as I’ve had before on another car and i know what to do when that happens). This was something entirely different.

I drove it for a few minutes with the metal grinding and then both the ABS/ESP/BAS lights came up and stayed on. The pedal doesn’t feel that floppy anymore and the metal grinding sound has gone but the lights are on on the dash.

I took it to my very friendly local indy and after doing the diagnostics, he stated that I need another ABS/ESP Control unit. He suggested that we should go for a second hand one as a new one would be cost-prohibitive.

A new one is not available from Mercedes anyway. I checked with Mercedes and even Mercedes suggested that I seek out a used one, they even gave me the part number A 0034311312.

The thing is that I cannot see another one anywhere on the net. Do you guys know whether this could repaired? and if so who could repair it.

My local indy is also doing some research and going to get back to me…

Any help and advice would be appreciated.

 

[mioba]

To be frank.

Anything can be repaired. It was put together in the first place.

key is competence to find the failed component, then a new component and replace.

Sounds easy doesnt it

 

[mioba]

ps get a second opinion. it could be a speed/abs sensor.

also AFAIK the control module needs go be coded to the car.

Had to replace one my w220 recently.

 

[mr_w140]

To be frank.

Anything can be repaired. It was put together in the first place.

key is competence to find the failed component, then a new component and replace.

Sounds easy doesnt it

it sounds easy but trust me it's not. I checked on the net, with Prestige All Parts, Dronsfields. Also checked with ECU Testing, but no joy. i will actually take your advice ( I was thinking the same as well) of getting a second opinion. The ABS/ESP control unit does not usually breakdown that easily on the W140's so it may well be one of the sensors...Thanks for that!

 

[LostKiwi]

The metal grinding noise was probably the ABS pump operating, which it would only do if it thought one or more wheels were under rotating.
Check the sensors for dirt and the reluctors for rust.

 

[mioba]

The grinding noise happens when abs not working . I been through this recently.
cause can be a sensor or a fault of the ecu.