Good morning

Let's talk about a topic related to the braking system of the Mercedes-Benz E-Class (W211)E 220 CDI (211.006) | 2002 - 2009 | 150 Hp | OM 646.961,  denominated "SBC braking system' (Sensotronic Brake Control); let us see in detail the Procedure for locking and unlocking brake cylinders for brake pad replacement.

Attention: before working on the SBC system, it is important to know a few details in order to avoid unconscious blocking of the braking system and incurring unpleasant consequences for the people working on it, as well as irreversible damage to the entire braking system.

For a safe intervention on the SBC system, it is imperative to first deactivate it using a suitable diagnostic tester.

In this phase the hydraulic pressure supply is blocked and also the brake system test. Access to diagnostics is only possible when the vehicle is stationary and the ignition is switched on.

Please note: access is no longer possible from a wheel speed of 2.75 km/h.

The diagnostic tester must be able to perform the following control and diagnostic options:

SBC deactivation
With the "SBC deactivation" function, the start-up of the accumulator recharge pump is prevented; only after this function has been carried out is it possible to replace the brake pads or carry out other work on the brake system (pipes, Abs unit, etc.). Furthermore, when the system is deactivated, the system is depressurised. In this condition, the service brake is no longer available.

SBC reactivation
With the "SBC activation" function, the accumulator charge pump blockage is eliminated and braking pressure is generated. Before starting the function, all work on the brake system must be completed and all hydraulic lines connected. Following the replacement of electronic control units, hydraulic unit or brake pads, initialisation cycles must be carried out. If a test routine has not been carried out after replacing the brake pads, the SBC system detects this and registers a fault in the memory.

These functions are present in Magneti Marelli diagnosis testers as can be seen in the image below.

Good work and see you next time...

• mercedesSBC