OBD2 codes.

Engine / equipment

Sensotronic Brake Control braking system: E-Class W211 and CLS C219 up to model year 2006, and SL R230

Period mentioned

2002–2012

Symptoms

Red messages in the cluster such as “STOP VEHICLE”, “Brake defective” or “Reduced braking power – visit workshop”, a hard pedal or little assistance, and pump noises when braking or opening the door. In a complete failure only the front wheels brake, using foot force alone.

Possible cause described

SBC brakes by wire: a control unit calculates the pressure for each wheel and a pump with a high-pressure accumulator produces it. The hydraulic unit has a limit on operating cycles; when it is reached, it warns and reduces assistance. The pump, accumulator and wiring also fail, and old brake fluid or incorrect bleeding make it worse. Mercedes issued several recalls and, in the US, extended the warranty on several system components to 25 years.

Check for the garage

With any red brake warning, stop driving and call for assistance. At a Mercedes dealer: read the SBC control unit with official diagnostics, check open recalls and warranty extensions by VIN, and change the brake fluid only with the procedure SBC requires. The cycles-exhausted warning means replacing the unit, not clearing the code.

Cost cited in the source

No verifiable estimate for Europe. In the US, Mercedes covers the hydraulic unit and other components for 25 years with no mileage limit; ask a dealer whether your VIN has a recall or extension.A rough figure from the original database, not an up-to-date quote.

Sources from the original database