New member here, w204, 2008, 166k miles, I occasionly get “ESP not available” which also stops kick down , cruise control, run flat indicator. Local Indy dealer diagnosed offside front wheel sensor faulty, replaced said sensor but still happens, Indy dealer asked if it was a genuine Merc part, didn’t know so replaced again with genuine Merc part, still happens. From this forum read about contaminated faulty “redactor “ ring so ordered new oil seal and inserted as described (pressed in with wooden block flush with casing) fault still occurs. Battery is a few years old but standing voltage within limits but did drive around with my caravan battery in tandem and jump leads to prove its not a low battery voltage problem. I have read about the brake light switch being faulty, is this a real problem??. Any advice gratefully received.

Hi Joe, I myself am trying to get this sorted on my 2012 W204. Mechanic has said the pump part of my ESP/ABS module needs remanufacturing or repair. I'm going to pick it up today and get the batteries done on the vehicle as they are quite old and see if that helps anything. You mentioned your car is stopping without brake lights ? could very well be a brake light switch trigger causing your issues. Will update the thread with my updates anyway

Hi Rawliii, ah, when I say stopping with no brake lights I meant the car stalls, bringing it to a halt rather than me applying the brakes!.

Hi Joe, how are you getting on ? any luck with fixing this issue? I swapped main and aux batteries yesterday and still no luck. May very well be the module

it’s getting worse, even stalled when starting it this morning. Going to clean the EGR and ordered a new mapp sensor, I am going to ring my friendly indi Merc garage tomorrow for advice but think I will end up renewing various sensors till it cured. My battery appears ok, if a bit old. I will put my caravan battery in tandem in the boot (in case low voltage is the problem) 🤞

Hi Joe, I had the same situation with my W204. I got a ECU, oxygen sensors and battery replacement and problem solved. Cost around $1800 right of my pocket. This was so recent as last sunday. Good luck!

OMG, I hope not, can’t afford that so trying to do little things, testing the inter cooler and pipes for leaks today, battery voltage tests ok. You mention oxygen sensor, I have read about the idle sensor but can find no information about it but a faulty idle sensor does seem to be sensible.

Despite renewing sensor (twice) and redactor ring garage still confirms same wheel showing a fault code fir that wheel. Wa# recommended I chase the wiring loom fir faulty connection. I bought a “Haynes “ manual but it dies not show ABS wiring 🤷‍♂️