BAS ESP Light.

[R-Connor]

Thanks for all the advice. Quite a lot to take in. I'm a little bit sceptical about the star test. I read a post on another forum where the test had indicated that the gearbox was shot. It actually turned out to be a reluctor ring. I have checked all reluctor rings and sensors and they seem ok. A quick look around the vehicle and engine bay didn't show up anything obvious except a bit of dirt and water marks on the ABS pump ECU.
I have got a slight knock on the front which i believe to be a drop link. I didn't realise this could affect the ABS.
I'll keep the investigation going and keep you all informed.

 

[jefrs]

Gearbox? - I do not know if it is applicable to your model but on mine there is a gland/seal from gearbox that can let oil into one of the ECU through the wiring. This is bad news but apparently an MB unit will tolerate it. Mine got a new set of seals at reasonable cost at indie (with oil & filter) - no, not new gearbox. Do check the gearbox fluid is ok, no water, if in doubt get fluid & filter changed.

Drop links are cheap too (must do both), other stuff get checked is ball joints and bushes. Checking 4-wheel alignment is a great idea, but not until you get the slop out of the system.
STAR/WIS is a good diagnostic tool but it doesn't substitute for common sense.

For some reason MB soldered electrical connectors on instead of crimping them like most other makes do. Brilliant idea! except of course they used RoHS lead-free solder, which corrodes over a period of years in a hostile environment, like a car. Fortunately it is easy to re-solder these connectors.

So steam-cleaned or jet-washed engine bay? - check the connectors, taking them off to inspect and putting them back is usually enough to clean them.