Mike500_Wagon

Hello,
I recently purchased a 04 E500 Wagon with 77k miles. In 2023, the previous owner took it to a specialty benz shop after the red brake malfunction message displayed on the dashboard. I am trying to determine if my SBC system has been replaced, or if only one component of the SBC was replaced.

Here is what they replaced:
1. Pressure reservoir for sensotronic brake control (SBC) hyrdaulic unit replace
2. Pressure reservoir (00-430-26-94)
3. Brake fluid
4. Hydraulic brake system bleed / vent

Earlier, in 2009, it was repaired at the dealership. I only have the VIN history report, which reads: Activate/deactivate SBC w/ brake system repair and brake fluid replacement

I don't see any notes about the pump or the control module. The accumulator and the pressure reservoir are the same thing, correct?

With the repair being in 2023, I'd imagine they'd replace the entire system, but maybe not. If not, i'm wondering if I can use the service record as evidence of failure and try to get it covered under warranty.

Thanks, from a "new" benz owner

bbirdwell

The pressure reservoir on your SBC system was replaced as it was on mine. When the pressure drops below 70 Bar the error message lights up alerting you to replace the pressure reservoir. The SBC unit's control board, high-pressure pump, and solenoids are still optimal. It's the control board failure where things get exciting. Be prepared to use manual downshifts and parking brake with left foot while standing on brake pedal with right foot like King Kong.
So...all is good.

Mike500_Wagon

thanks. I'm on the fence about just replacing it myself even if I have to pay. One thing I wasn't able to figure out... are the replacement parts basically the same as the original parts, or did they make improvements? Do you just benefit from a newer part, or do you run more of a risk b/c you introduce installation errors etc while changing out a working part

bbirdwell

The system must be depressurized prior to working on it. Otherwise things can get spicey. STAR/Xentry or an advanced scanner can do so. The system then needs to be reactivated prior to starting the engine. Yes, there are those who just unplug the SBC to change brake pads but going into the actual SBC unit itself is a bit more challenging.
Multiple iterations (part numbers) for the SBC; could be internal hardware changes or software modifications. Electronic Parts Catalog will show all versions that fit and indicate which ones supersede the previous version.
Since it is on a 25-year replacement coverage, I took mine to the dealer and let them replace the reservoir. There was no cost to me and they even washed my car for me. My dash cam recorded some "interesting" video of the work and the test drive. I regarded it as "no harm, no foul" so did not raise the subject with the service manager.
See attached technical info on the system.

nd-photo.nl

Contact your local Benz dealer and let them check if that SBC unit was replaced under warranty. I got mine replaced last year, fully under warranty. I needed to wait about 2 hours while they did all kinds of tests and getting it authorized.

Unfortunately, they didnt provide me with an invoice or proof that it had been done. But it can always be looked up in the official MB system, as the repair is logged there.