jameshobcraft

Help!

I have a 2009 S350 with a "Parking Brake Inoperative" yellow message.

Background:

The EPB module was replaced, since then the error has displayed.
The gateway and front SAM have also been replaced and the error still displays. (Damn it!)

I have adjusted the brake shoes and the brake works perfectly if the fuse is removed for a period and re-installed. With the key in the on position the brake will engage and disengage completely normally, with the correct red dash light illuminating when the brake is engaged.

The yellow warning fault appears straight away as soon as the car is started. From that point onward, whenever you press the button you can hear the brake engage, but as soon as you take your finger off the button it immediately disengages and will not stay on.

It seems that it is not possible to scan the EPB module, despite the switch activating the unit, the scanners both STAR and other generic units cannot communicate with the EPB. Which is why the diagnostics shop changed out the gateway and SAM unit.

I am pulling my hair out with this problem - the rest of the car is outstanding, but it is kinda useless if the park brake won't function as I can't use it on the road without that functioning!

Any advice or suggestions on how to overcome this problem is appreciated.

MBCO

You should get your car scanned using MB tools like Xentry to understand what the root cause of the light represents. Don’t throw any more parts at the problem until you do.
Please report back with error codes and then forum members will be better able to assist you.

BOTUS

there is a teach in process to the module you can do when you fit new brake shoes - there's also a LOT of info about the park brakes that even now cheap autel diagnostic kit can tell you about - sounds like the new module doesn't work.... or the car doesn't understand what it is... there is a counter of how many times its been operated... I guess you never found that out before they took out (what was likely a perfectly good module) and fitted a broken one ?

if you remove a module and correctly fit another its never handed back broken... the job was not completed, either

workmanship - forgot to plug it in connect the cables to the drums etc.
the new unit is not working correctly
the software side was not undertaken because they don't have the right gear or such

lkchris

https://www.youcanic.com/mercedes-be...owners-manual/

TURBO-BS

Hello,
I have the same issue. How did you fix it?
I replaced the module with an aftermarket module.

It works some time if I unplug the plug and plug it in again.

BOTUS

a lot of electronic parts on most german cars are not a straight swap and they just work... to ensure the car was ONLY repairable by the manu to rob more money - they made either

1) the vehicle chassis number has to be written to the replacement module - using specialist manu specific dealer electronic diagnostic tools
2) a calibration process is required - using specialist manu specific dealer electronic diagnostic tools
3) a reset of a module is required - using specialist manu specific dealer electronic diagnostic tools
4) specific fault codes need to be cleared - using specialist manu specific dealer electronic diagnostic tools
5) other madness to ensure you need to be - using specialist manu specific dealer electronic diagnostic tools

these days due to EU anti protectionist laws - third party stuff is out there - but its a minefield of fun and games trying to get everything done correctly - particularly for complex safety related junk as the manu deliberately wrote garbage procedures to stop anyone getting it sorted correctly

on a car as deliberately complex as the W221 its another level of hell - check adverts for BenzNinja - one of very few people in the world who has ANY idea what is going on - and the only nice guy doing it anywhere on the planet

https://mbworld.org/forums/s-class-w...a-s-n-1-a.html