Mercedes E-Class - ABS warning light activated
Mercedes Benz
E-Class (W211)
Model year 2002-2005
All models with electro-hydraulic brake system (SBC)
ABS warning light activated
Error codes in the control unit:
C0249F "Duty cycle too high"
C2258 "ABS braking time"
If these error codes are read out of the ABS control unit from the vehicles specified above, a possible cause for this could be that the service life specification of the ABS control unit and hydraulic unit has been reached.
In order to ensure a safe mode of function of the system, the system manufacturer has stored a service life of the components in the control unit. Next to the duty cycle of the pump, the control unit also records the braking actions already carried out.
If a certain brake counter value is recorded, the so-called service threshold is reached and the hydraulic fluid must be replaced.
Procedure
These error codes must not necessarily lead to the replacement of the hydraulic fluid SCB ( figure).
In order to be able to rule out other causes, first check the periphery of the brake system. The ABS hydraulic unit must be replaced only after there are no more electric and mechanical error to be diagnosed.