Quote:
Originally Posted by mannys9130
The accumulator is emptied via a solenoid valve. If the unit shuts off, you have no access to that fluid. If it shuts off, you're left with the emergency MC and poor braking power.
Sometimes MB does things well, and sometimes poorly. You'd think the SBC would wait to shut off, but you'd think the biodegradable wiring harnesses would wait to disintegrate until they're junked. We know the latter is not the case.
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OK, once more, with feeling.
I stated that if the pump fails, at minimum, assisted partial braking will still be availible for a limited number of applications. This is covered in the " Fall back level " statement " A " ( my lettering ) quoted at bottom from
Welcome to the W211 E- Class! and by careful reading of the hydraulic diagram
Welcome to the W211 E- Class!
Looking the hyd diagram, brake actuation solenoids y6 / 8 / 10 / 12 are normally closed. I'd expect this condition to continue the pump fails. This is also supported by the " Wake up function " quoted below.
Solenoids Y7 / 9 / 11 / 13 must be closed by applying electrical power to allow powered brake pressure to rise. In the event of pump failure, there is no need to dump system pressure.
As for the shutdown timing and bio wiring, you are mixing software programming and chemistry. It would be a real stretch to think the programming was purposely designed to shut the system down _in flight_ just because it hit the max brake applications. It is trivial to program in:
IF BRAKE_APP = 600000 and WAKE_FUNCTION = 1 then RED_ERROR_SYS_OFF = 1
MB didn't design the SBC on it's own, Bosch was also involved.
"" Wake-up function
The aim is to wake up the SBC before the brake pedal is first operated. This enables the reservoir to be replenished, if necessary, by operating the reservoir charging pump. In addition, . . . ""
"" Fallback level
Specific deactivation levels are incorporated in the SBC depending on the severity of a fault defined in the system. The individual fallback levels are listed in the form of a table:
- A — servo assistance by means of muscular power brake at front wheels and brake pressure buildup by SBC at rear wheels (active braking force assistance).
- B No braking force assistance (only hydraulic backup at front wheels). ""