SBC Brakes onW211

[Alex Crow]

OK please read page 24 what happens then when it does not wake up
http://www.mercedestechstore.com/pdfs/R230_adivsor/218 HO SBC (WJB) 09-30-02.pdf

on page 24 it clearly says that the wake up signal comes from the left front sam. however, this document is only used to give a system obverview and is not entirely accurate! it says that of the many events that can wake up the sbc unit, pressing the brake pedal is one. but the brake pedal switch and travel sensor are wired direct to the sbc unit. why design it to rely on feedback from a sperate module when it has the signals wired direct?

i note on closer inspection of wiring diagram that there ARE direct wiring links with nsf and rear sam units, but these will be very simple communication routes with voltage coded or similar signals (eg rear sam will get a message to say activate brake lights, probably just a voltage either on or off).

 

[television]

Well it still happened, and nothing on the SBC pump or ECU was replaced, that only leaves electronic data buses.

None of the items in the start up for the SBC are programmable in their own right, and just opening a door wakes it up,, this is all shared data and can easily get mixed up when moisture is involved

 

[Alex Crow]

...nothing on the SBC pump or ECU was replaced....

do you really believe that malcolm?

 

[television]

do you really believe that malcolm?

It is easy to open the bonnet and take a look

 

[television]

I am going to have to abandon my test today on an air strip,, if the engine is started with the SBC deactivated, then many activations must be done to the SBC system and I do not fancy being stuck with a flat battery and no back up power supply, also for the STAR some re thinking is needed

I will just go and have a nice carvery lunch for now

 

[Alex Crow]

I will just go and have a nice carvery lunch for now

have you put a new battery in the scales again malcolm

 

[television]

have you put a new battery in the scales again malcolm

Nope,,just one bread roll for midday rather than 2 just in case my SBC fails and there will be less weight in the car

I really appreciate all of your input on this Alex and as you know I respect you highly, every avenue that is opened all helps into what went wrong

 

[leeey]

I have just have now purchased a W211 05 plate 280CDi.

I have a whirring noise I think is coming from the SBC unit. This occurs when apply the brake pedal and sometimes randomly at low speeds.

This may sound a bit odd but how do you know whether a pump has reached the end of its life. What are the syptoms of a pump reaching the end of its life and do you think mine has?

I am not seeing any warning lights and I'm not experiencing any problems with braking.

 

[television]

I have just have now purchased a W211 05 plate 280CDi.

I have a whirring noise I think is coming from the SBC unit. This occurs when apply the brake pedal and sometimes randomly at low speeds.

This may sound a bit odd but how do you know whether a pump has reached the end of its life. What are the syptoms of a pump reaching the end of its life and do you think mine has?

I am not seeing any warning lights and I'm not experiencing any problems with braking.

There is a mod for the noise when the SBC braking system runs, it is a pulsation damper fitted to the brake lines.

The pump will get changed when it has reached the end of its working running time and this normally gets picked up during a service. In the event of a failure the dash will go red leaving you with just 10% of the original braking