helmutcar

All,

Does anyone have experience with an SBC issue in an SL55 '07 or later model year?

From what I have read, it looks like there was a recall and extension of the warranty on the SBC unit up to 10 years for the '06 model year and below, but I can't find anything on later models.

I am at about 66K miles on my '07 SL55. Several weeks ago, I had just left my house when the big red brake warning light came on, and I lost power to the brake system. Fortunately I was on a local road, not going very fast, and was able to stomp down on the brake pedal to slow the car down. After a few moments I turned the car back on, and the error had cleared. I was able to drive it normally to my mechanic (independent shop), who ran some tests and said that the error was pointing to the SBC system, but that he had never replaced one and wasn't 100% convinced that this was the problem. He thought it might be somehow related to the battery, which was at about 60-70%. He recommended we wait and see.

Over the weekend, my husband noticed that the red battery light was on in the car. He drove it that night without any issues, but the next morning (red battery light still on) the same issue happened with the brake system. And, after a short time, it cleared itself out and worked fine.

So, I'm wondering whether anyone has ever dealt with a similar type of issue, what the resolution was, and whether there is any hope that this somehow gets covered under a warranty. From what I can tell these units are very pricey.

Thanks in advance!

cal1

Let me start by saying I am far from an expert on SBC braking issues. That said, I will share with you what I have come to understand about some of the SBC problems. Keep in mind, my understanding is far from comprehensive and 100% accurate.

Your situation sounds to me like an SBC failure. SBC is essentially a "brake by wire" or electronically controlled braking system that is capable of some amazing things when working properly. Bosch, the maker of the system built in some safety features so that if the electronic portion fails, some braking still exists. Check out this diagram:




If you look carefully at the diagram, you will see that significant travel or pressure on the brake pedal will actuate the back up hydraulic braking system which only applies braking to the front brakes. Given your post, it sounds to me like that is what happened.

Because the SBC system is electronic, Bosch/MB saw fit to build in an operating threshold limit. They decided that once the brakes have been actuated 300,000 times, the unit should be replaced. When the 300,000 threshold limit is reached, a white "BRAKES" warning comes up on the multi-function display, not red. There is also a hydraulic portion of the SBC system that is known to fail. I am not certain, but I think when that fails, all electronic braking is lost and a red Brake warning is indicated.

Regarding the warranty. MB has established a 10 year warranty on the SBC system, but it is only for a few very specific damage codes. Below is the warranty doc.




My suggestion to you is either find an independent who can read codes for you or take it to a dealer and have them read the codes. You might get lucky and have the SBC unit replaced under warranty.

I am currently dealing with the "service threshold reached" issue and am outside of the 10 year warranty period. I plan to replace the unit myself. A number of members have done this. To do so safely, SBC must be deactivated which takes an MB diagnostics tool such as the Xentry DAS system. There actually is a workaround to stop SBC from activating while it is being worked on, but I am reticent to discuss it.

Not to inundate you with tons of info, but here is a link with more discussion on the subject. Be careful though because other issues unrelated to failed SBC are discussed as well.

https://mbworld.org/forums/e-class-w...-easy-diy.html

Good luck!

carguyshu

to figure out the true problem you need a star tool. I keep hearing this 300,000 actuations number and just now got the brake light on. When I checked with my star tool it said I had 423,000 actuations, so I dunno how that happened. Either way I just ordered a new SBC unit from huskerparts.com for $850. This was the cheapest place I could find one and it is my understanding it takes 3-5 hours to replace, in part because everything in the system will need bleed with new fluid.

helmutcar

Thank you for the info, Cal1. It was very helpful, not too detailed at all.

So, here's what I'm wondering...the recall letter that you posted was dated 2009, but from what I can tell the original recall campaign was in 2006. So, if I have the correct codes (I have to check, it's on my paperwork from the shop, which I don't have at hand), would my vehicle be covered even though it is a 2007 model year? The notice you posted DOES say all model years for the 230 model, but if the original recall was from before my car was even produced, could it still be covered?

cal1

I am reasonably certain that as long as you have the correct error codes, your car will be covered.

I have looked at many threads on multiple websites so I have forgotten where I read this, but one guy was talking about paying his teenage son to sit in his car and actuate the brake until the service threshold was reached. I would have done the same thing, if I would have known back when my car was getting close to 10 years in service.

Please share what ends up happening with your 07. I have been trying to compile data and error check it so I can post a comprehensive thread on the subject. Most of us R230 folks are going to deal with SBC at some point.

helmutcar

So, called the dealer, and assuming the car has the correct error codes, it would indeed be covered. The car is at the body shop right now to deal with an unrelated pothole issue, but I will post an update as soon as I get it back and can take it to the dealer for a diagnostic.

Thanks again for the help! Fingers crossed that the car obeys and throws the right code at the dealer's!

carguyshu

with a star tool you can check how many actuations you have on your unit and how close you are to needing replaced. If you have developer mode you can change that number up or down at any time, which might be an easier thing to do than sitting there and pushing the pedal over and over again...

helmutcar

All,

I wanted to come back and post a quick update. I took the car to the dealer, and the issue was in fact the SBC pump. All of the work was covered under warranty. Woo hoo!

Thanks again for the help!

cal1

awesome!

Thanks for popping back in and updating us.