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Relax, some of us don't live on here. If you want to have immediate access to the codes, invest in a real diagnostic system and not just a code reader.
C24FC - Terminal 87 undervoltage - process any other fault code which occurs, erase fault code. Note: this fault code will be set if you turn off the ignition with vehicle speed > 6 km/hr before vehicle comes to a stop.
C2131 - Pressure Reservoir Faulty - replace pressure reservoir
C25D5 - Hydraulics fault: malfunction in pressure supply - before doing anything with this code check to see if the power supply of control unit N47-5 is ok. Next, process all other current fault codes. Then, bleed brake system as this could be the cause.
C249F - Check operating time of component A7/3 (SBC Hydraulic Control Unit) - Obtain the number of actuations.. Test voltage at terminal 87 of control unit A7/3n1 (SBC Control Unit). Test ground cable.
Start with C2131, the pressure reservoir. If you don't have the tools or the diagnostic system to work on it, take it to the professionals at the local Benz dealership or a trusted independent. The codes will need to be erased after repair. SBC system can take your fingers off if you do not understand how to disable it.
It sounds like your SBC unit has hit it's service threshold. Also some hydraulic issues related to SBC. Because SBC is essentially "brake by wire" Bosch and MB put a service counter in it. Based on my research, that number is 300,000 brake acuations.
If it was me, I would tow the car to the nearest dealer or trusted independent who is very familiar with SBC and have them replace the SBC unit with a remanufactured unit. I am sure a number of members have done the replacement job themselves. SBC is under high pressure so cannot be activated will working on it. Also, not even the smallest piece of dust can get into the system without causing trouble. Finally, while performing some of the actuation procedures, SBC uses a ton of electricity. A proper battery assist is needed.
I recently had the service threshold issue with my SL. After reviewing the install procedure in my STAR/DAS/WIS system, I decided to let the dealer do the work for me.
Here is a diagram of the SBC system. When you get the red message you got, the only braking you get is the back hydraulic system which only brakes the front wheels. I have heard the brake pedal needs to go almost to the floor in order to get any braking. A very dangerous situation if you ask me.
Thanks. I see some new reservoirs on eBay at $200 or less. Let see what's happen after replacement.
Just a guess, but I suspect the red warning will disappear, but the white warning will not because of C249F. I don't recommend it but if your SBC has reached its service threshold, its counter can be turned down. There are even inexpensive tools to do it, just search mercedes sbc reset tool.
Again, I would not recommend doing anything but replacing the whole SBC unit if the service threshold has been reached. As you know, these cars go fast in a hurry. They need to be able to stop fast too.
2003 E55, 2003 SL55, 2014 CLS63, 2018 q50 Redsport, 1968 Camaro SS, 1999 Trans am Firehawk
there are part number revisions happening for the SBC all the time. The cheapest I found was at huskerparts.com (they are a merc dealer in nebraska). You can no longer buy a new SBC unit, only rebuilt ones. The part number they have for it on their website is an old part number that is no longer valid. Just call them and they will hook you up with the newest version
