KAROZZA

Hello!

YOM 2002 & definitely on the original SBC. Now just covered over 26600 miles.

So, I am just about to start enjoying the last day of my mini holiday touring eastern Sicily & about to drive out of the gate from the B&B when I hear a sudden thump(similar to hitting the car's undercarriage on a ramp) as soon as I hit the brake pedal; then, no brakes

Warning lights in RED in both displays & beeps galore; I stopped breathing. Where, you might ask, in Trecasgni at an elevation just tipping 1900ft; all down hill with no brakes The previous day did a lot of driving up & down & lots of fog.

First things first, warning lights, as I can recall as I was still in shock(I couldn't breath; remember!), right display kept stating Reduced Brake Effect, Visit Workshop! Left display:STOP-Brake Defective but also, kept showing ESP failure after switching ignition on.

Anyways, started breathing again & managed to get to a Petrol Station with extreme caution, filled up tank. As I started making phone calls, after parked at the side, I switched ignition on, heard the usual noise from the SBC pump; everything back to normal!!!!

I then drove carefully the 2 hour plus drive back to the ferry, visiting some towns on the way; all good. Got back to Malta & even did some sudden but not extreme braking; all good.

Is it normal for SBC to fail & then come back in service; does this mean a replacement is needed??

Took the car on STAR for diagnostics & confirmed SBC has not expired but suggests replace & bleed brake fluid....couple of weeks later booked car for the procedure....

Well, I took the SL in today to have the brake fluid replaced. Up till now, had no faults whatsoever. Picked up the car, all good, drove maybe 5KM down the road to my shop, parked the car & switched off. after 5-10 minutes went back to the car & started the engine; again, a bundle of warnings including the continuous beeping from the both displays.

Apart from Brake Defective. Stop Vehicle! got: Incr. braking distance Start Engine! Also ABS light stayed on.

This time though I drove the car in to the shop & the brakes were still working

The engine felt like it was hunting & running slightly erratically in drive with the brakes & even in Park at one point.

Any assistance will be really appreciated

KAROZZA

Some pics of display warnings.....well trying to as it's only uploading one photo

KAROZZA

....

KAROZZA

.....Apart from the usual ESP

sgaar

Well, that is a nasty light show you have there... SBC is one of those systems you cannot diagnose without SDS. If you don't have one yourself, you will have to find someone who does such as an MB dealership. The good news is that MB extended the warranty on the SBC unit (at least in the US, but I believe it is worldwide) to 10 years, unlimited miles, so if it is the unit you should be able to get it replaced under warranty.

KAROZZA

Unfortunately the YOM is 2002, so even if the extended warranty applies here, this has expired. If indeed the fault is the SBC. When tested on STAR it has not expired(the amount of use needed for it to be replaced) In fact I'm trying to establish replacing to solving the issue.

I have read, the SL is very sensitive to battery & its electronics thus I have just learned that the consumer battery(in the boot) should be an AGM battery, which mine is not!? Some have had similar issues because of this.

So, I'm trying to find out if anyone has been using a normal battery(boot) for some time without any issues?!

latemodel21

Please clarify ... was there any noticeable dis-function or change in feel of the brakes during either (or any) of these episodes? If so, please elaborate.


Thanks,
Chris

KAROZZA

Hi Chris,

On the first occasion, I did lose the brakes & the pedal had to be pressed way down to have very minimal effect just like SBC failure.

This week's event, although similar plus the additional start engine warning, was different as in this case, I still had brakes!

As this happened a few KMs after I took the car for a brake fluid change, I asked the mechanic & he explained that the procedure is mostly done using the consumer battery.

The previous owner had replaced the boot battery but although a 70Ah battery, it is not an AGM Battery.

The first incident happened on the 18th of May & up till this past Monday's brake fluid change, there were no issues.

latemodel21

Thanks for the quick reply Karozza,

I replaced my original SBC in my 2003 SL55 after 10 years and 2 months (yup ... missed the warranty) and now my second is giving a code for internal hydraulic failure (after only 2 years ! ... yup ... not in warranty this time either) ...

So, I was curios what the brakes might be like if it goes from white to red while I wait to install SBC #3 which is shipping this week.

Worth mentioning, if you install it yourself and/or have an indy do it with an out of date Star tester, it will likely say the new unit needs programming ... they don't, they are already programmed.

Cheers,
Chris

KAROZZA

Chris, where did you buy the SBCs from & how much??

latemodel21

I bought them from OEdiscountparts.com The first was $790 plus core ... the second was a bit less (because I do a lot of business with them and they felt bad about the short life of the part, they gave me the second replacement at their cost).

Cheers,
Chris

KAROZZA

What brought your attention to check the code for SBC internal Hydraulic failure??

latemodel21

Less than 1000 miles back, I got the white message "BRAKE" and "Service brakes Visit workshop" (see pic) In star I get a C2130 code (see 2nd pic) which I have cleared several times and then it comes back in less than 100 miles. For this Code, WIS does not offer any diagnostic, only ... "replace Unit A7/3" .

Cheers,
Chris