AKAustin

Ok, so my 2006 W211 has 230,000 miles on it, and as far as I know still has the original Sensotronic Brake Control module. I'm trying to figure out how much life is left so I scanned the module using the STAR diagnostic scanner. Now I need help understanding and interpreting what these values (listed below) mean. As far as I know, I have 750k brake actuations which seems to be way more than other numbers I've seen reported, yet the life expectancy is showing 46%? Also my pretensioning pressure is only 68bar and below the 72bar threshold. I am not getting any codes currently. No instrument cluster warnings, nor codes picked up in SDS.

So what do these numbers really mean? Is the SBC on it's last leg, or does it have life left? Should I replace the entire SBC with a $1,000 remanufactured one now, or can I fix the low pretensioning pressure by replacing the $100 accumulator?

DJ_GetBRLiveTime: 750608
DJ_GetPmpCycle: 27882500
DJ_GetPmpLD: 46.625008

SBC pedal value sensor: 18.0mm
Front axle pre pressure sensor: 7.7bar
Left front pressure sensor: 6.9bar
Right front pressure sensor: 7.3bar
Left rear pressure sensor: 0bar
Right rear pressure sensor: 0bar
Reservoir pressure sensor: 120.8bar
Pretensioning pressure of pressure reservoir: 68bar
Temperature: 42C

kajtek1

750k pedal pushes sure is the record.
I did hear from MB technician that the number should be 600k before pump rebuild, but it is also affected by other factors, where pump cycles show the count as well.
Are you the original owner? I would think somebody erased something in computer?
Frankly the number would really worry me. If you decide to drive it for longer, go to empty lot and practice some emergency braking with SBC plug pulled.

AKAustin

I am the second owner. The original owner was a wealthy couple who knows next to nothing about cars and basically took it to the MB dealership anytime there was an issue, and they used various independent mechanics for smaller things (i.e. tires, fluid & filter changes, etc.). If someone did alter the SBC parameters to raise or reset the values, it would likely have been the MB dealership. However, I really don't know much about the vehicle history as I only received the latest few months of maintenance records. The original owner tried calling the dealer to release the full records to me, but they refused and said she had to come in person.

What I'm trying to figure out is how to tell what the wear is based on the values? I.e. is the pump still strong, and is it just the accumulator that is leaking (which I can replace for cheap), or is the whole SBC unit worn out and I should replace it with a refurbished one.

bbirdwell

If you have access to a STAR computer you have access to the service records recorded in the Central Gateway. Just cross-reference the Service numbers to the attached service sheets. This is why it is important for you to use the FSS as designed.

https://mbworld.org/forums/showpost.php?p=7250102&postcount=1147

FWIW, I would replace the entire assembly as preventive maintenance. If not, just the accumulator. You can be the guinea pig to see how many actuations the SBC will go before it quits on you. Also, zero Bar pressure on right and left rear does not look right.

EDIT: no reason you cannot go into the dealer yourself and request to go over the service records. No reason they cannot redact personal info and make a copy for you.
New edit: looking at the attached document, part of Service 9 is to check the preload pressure of the pressure reservoir; that implies the accumulator.

rapidoxidation

That attached PDF file is one of the many gems on this site that keep me interested.
Printed a copy and saved the file as well.
Thanks bbirdwell!

bbirdwell

You are welcome and here is a better version.

kajtek1

Those service sheets pops right and left every couple of years.
I don't see them addressing transmission service and they only go to 150k miles, when my cars are above that
Suppose the first wearable on SBC are motor brushes, but again, MB rebuild whole units for a good reason.

rapidoxidation

AKAustin

That's pretty interesting bbirdwell, thank you for the that info. I checked the central gateway and it did have some service record info that correspond to the service sheet you provided, but it seems to lack any info related to unscheduled services (e.g. I know the injectors were replaced recently to the tune of $4,000, but that's not showing up, nor seemingly anything else that would be considered unscheduled maintenance). As for the rear pressures, I'm new to the SDS tool and probably messed the test up somehow. I'll try to perform another test and see what happens.

I guess my hangup is I don't understand why my SBC is reporting ~47% service life if the consensus is it should be worn out due to mileage and 750k actuations. I didn't want to replace an expensive part if it was unnecessary, but I'm thinking I may just eat the cost and order a new SBC so that I can be confidant in the car.

As for the service records, I'm only relaying what I was told. I went to the dealer in person, and the "specialist" informed me that it was against MB policy to share service records under any circumstance unless the original owner showed up in person with their driver's license to verify their identity.

bbirdwell

Here are a couple of good threads:

https://mbworld.org/forums/e-class-w...pump-w211.html
Pump cycles old unit ~10M, pump cycles new unit ~18K. CDIJeff listed pump cycles but not the old unit actuations. New unit actuations (Bremsenzahler) were 1382.

and

https://mbworld.org/forums/w211-amg/...d-reached.html
Joe had ~556K actuations indicated on Bremsenzahler when it gave the white warning. He did not list the pump cycles old and new.

This is sort of like a puzzle....