SBC activation problem with Foxwell NT520
Thread Starter
Junior Member
Joined: Nov 2015
Posts: 27
Likes: 2
From: Nashville, TN
2018 S450 4-matic W222
SBC activation problem with Foxwell NT520
Car: 2005 E320 Base Sedan, Gas, Left Hand drive, 200k miles +
I replaced the hydraulic accumulator on my SBC unit since it was showing no pressure and throwing the standard 'Pressure Reservoir Faulty' error, C2131. I used a Foxwell NT520, fully updated, to disable SBC. This worked perfectly and there was only a tiny spray of fluid when I removed the old accumulator. The new one went on fine.
The problem I'm having is re-activating SBC. I'm following the very basic instructions that come up on the machine as best as I can, but it gets to a spot where it shows the pressures of the four brakes sitting over 60 bar. It sits there showing those pressures and gives no option to continue, just options to pause, show graphs of the pressure, and save. Pausing does nothing but pause the display changes. Graphs show graphs, and save saves the numbers and never stops. Enter does nothing, so after pressing Back, a new code shows up that SBC is disabled and I have to use a different box to clear it. C2131 still shows up, but my box shows pressure in the accumulator around 120 bar.
Am I not waiting long enough? Is this something I should go through Foxwell to handle? Am I doing something out of step? Do I have to do a brake bleed before it will re-activate correctly? I'm feeling a little lost. Is there anything I can try before taking it into my mechanic/dealership to get the brakes bled and my work checked over?
I replaced the hydraulic accumulator on my SBC unit since it was showing no pressure and throwing the standard 'Pressure Reservoir Faulty' error, C2131. I used a Foxwell NT520, fully updated, to disable SBC. This worked perfectly and there was only a tiny spray of fluid when I removed the old accumulator. The new one went on fine.
The problem I'm having is re-activating SBC. I'm following the very basic instructions that come up on the machine as best as I can, but it gets to a spot where it shows the pressures of the four brakes sitting over 60 bar. It sits there showing those pressures and gives no option to continue, just options to pause, show graphs of the pressure, and save. Pausing does nothing but pause the display changes. Graphs show graphs, and save saves the numbers and never stops. Enter does nothing, so after pressing Back, a new code shows up that SBC is disabled and I have to use a different box to clear it. C2131 still shows up, but my box shows pressure in the accumulator around 120 bar.
Am I not waiting long enough? Is this something I should go through Foxwell to handle? Am I doing something out of step? Do I have to do a brake bleed before it will re-activate correctly? I'm feeling a little lost. Is there anything I can try before taking it into my mechanic/dealership to get the brakes bled and my work checked over?
Thread Starter
Junior Member
Joined: Nov 2015
Posts: 27
Likes: 2
From: Nashville, TN
2018 S450 4-matic W222
Apparently it was detecting some air. I deactivated SBC this afternoon, tried to reactivate, let it sit at the pressures screen for about 10 minutes, then ran the bleed function again without actually opening up the bleed valves. This reactivates SBC. I then rolled around an open parking lot looking at pressures and RPM indicators. They all worked. The C2131 error would not clear, but lo and behold, this evening the brake message disappeared at startup and at shutdown. It may be that some air was in the system or the error had to go away internally for some time/miles before it would erase.
Either way, I'm happy. Now to get the headlight assembly replaced, swap out the driver's side arm rest on the door, and eventually get the passenger WSS fixed so the SRS light will stop and I can trust that the airbag will deploy.
Either way, I'm happy. Now to get the headlight assembly replaced, swap out the driver's side arm rest on the door, and eventually get the passenger WSS fixed so the SRS light will stop and I can trust that the airbag will deploy.
Junior Member
Joined: Aug 2015
Posts: 17
Likes: 1
From: NewYork
SL55 AMG
seems an interesting scanner. i found this on google
Foxwell NT520 Mercedes Function List
sorry to post a link
Foxwell NT520 Mercedes Function List
sorry to post a link
Thread Starter
Junior Member
Joined: Nov 2015
Posts: 27
Likes: 2
From: Nashville, TN
2018 S450 4-matic W222
Right now, my biggest complaint is that it's slow. I've had this and an iCarsoft box. The iCarsoft was much faster, but didn't have the active pieces like the Foxwell does.
Well, I guess if I'm not ready to drop $700+ for a Star system, I'll have to put up with the quirks of a different item.
Well, I guess if I'm not ready to drop $700+ for a Star system, I'll have to put up with the quirks of a different item.
Junior Member
Joined: Jul 2011
Posts: 33
Likes: 1
From: Houston, Tx
2006 E350, 1964 & 1967 Vette
i was looking at the foxwell nt644 to bleed my system (2006 E350) after having the sbc unit sent out and rebuilt by modulemasters. what kind of problems did you run into when you were doing your sbc?
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Thread Starter
Junior Member
Joined: Nov 2015
Posts: 27
Likes: 2
From: Nashville, TN
2018 S450 4-matic W222
Biggest problem was directly activating the brakes once I deactivated them. If I deactivated, then attempted to activate, it would get to the point where it pumped up the brake pressures to ~65, then it sat there with no option to go forward. I ended up solving that by going through the brake bleed section, but not actually bleed the brakes. That activated the SBC unit just fine.
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Newbie
Joined: Aug 2020
Posts: 5
Likes: 4
SL55
Worked for me. Thanks.
Biggest problem was directly activating the brakes once I deactivated them. If I deactivated, then attempted to activate, it would get to the point where it pumped up the brake pressures to ~65, then it sat there with no option to go forward. I ended up solving that by going through the brake bleed section, but not actually bleed the brakes. That activated the SBC unit just fine.
It was doing my head in trying to figure out how to erase the error which kept popping up on my dash. Yeah thank you.
Last edited by Jason2704; Sep 3, 2020 at 09:25 AM.
