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Thought I might ask this question here as someone may have some insight as the w211 and r230 share the same brake system. Posted it on the w211 section, but not so busy over there.
Got the brake warning and failure on a 2003 e55 73,000 miles and am thinking it’s the accumulator that has gone south. The current bar accumulator pressure is 140 bar, the unit does run, but not when opening the door and only after pushing the pedal softly 2 times.
The sbc motor only runs for about 2 seconds or so. I bought a new accumulator and was going to depressurization it, replace it, and bleed the brakes. What are the symptoms of a bad accumulator? Seems like I remember the SBC motor staying on a bit longer than it does now, and not coming on after 2 slight pushes of the brake.
My car is a rebuilt salvage, so the US extended warranty doesn’t apply, and yea I do have a diagnostic tool to deactivate and activate the SBC. I unfortunately cleared the codes (which it had a few) and didn’t write them down. The codes haven’t returned but I haven’t driven the car on the road as having little warning and no brakes isn’t really something I want to go through again.
Sounds like an accumulator, but I think your are wrong about the rebuilt salvage voiding the warranty. To be more specific, I just had an SBC unit replaced on a 2003 SL500 with rebuilt title under warranty. Lemon law buyback might be excluded, but rebuilt title should not.
STAR/Xentry will give you the exact issue code. Accumulator is considered failed when its pressure is 70 Bar or below. >70 Bar no errors thrown. The issue you describe sounds internal to the SBC unit.
SBC pressure motor runs for various periods of time (20 seconds to several minutes) depending upon inputs but 2-3 seconds is not one of those scenarios.
I've posted the SBC technical training info multiple times in the past in the W211 AMG sub-forum. If you can't find it, PM me with your email address.
What are you using to query the SBC?
Last edited by bbirdwell; Dec 23, 2023 at 10:19 PM.
I would think you would have a current code if your pressure was at 140. I took a picture of the DAS screen when I was doing my SBC diagnosis. For "pressure regulator" is shows it should be at or above 145.
I'm assuming that's what you're tool is measuring as the pretension pressure is between 69-110. I'm also assuming the R230 and W211 are the same sbc as the sbc unit I bought showed both r230 and w211 as compatible.
If you don't have a code, maybe the pressure is intermittent. If you had a DAS computer, there is a graph there that shows you the pressure over time which would be helpful.
I certainly would like to be wrong about this, when I had the fuel pump leak issue, the dealer said it wasn’t covered because it’s not a safety recall. I have been told that the SBC is an extended warranty and something Mercedes does to get around a government mandated recall, but that could be incorrect as well.
Is it a safety recall like the sunroof on the w211 and w203 or extended warranty? Should be a safety recall, as it is very dangerous.
You have to have codes that indicate a faulty accumulator or SBC unit. Since you cleared them, you have to wait for them to come back before they will do anything under warranty. I made the mistake of turning off the life limit (thought I was just clearing the dash warning). Ended up having to turn it back on in developer mode so it would reset the SBC end of life code.
So after going around with the dealer, it’s a non warranty deal with a salvage car. If it’s not a recall which it certainly should be, they circumvented the recall by doing the “extended” warranty. I bought an accumulator and will try that.
Really should get rid of this car as well, between the r230 with these brakes and the BCM fire issue and this car, I feel like one of them may kill me. I can tell you that I am not fond of having no brakes with a warning telling you there is no brakes out of the blue. I will put up with the “maintenance” , but this is getting dangerous.
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