Is a faulty SBC/ABS unit repairable?

Thursday December 5 2019


By Paul Kaganzi

Hello Paul, I drive a Mercedes Benz E240 W211 2003 model, which I bought from a friend. He told me the only problem it has is a faulty SBC/ABS unit. Is this repairable? What if I decide to ignore it, is it dangerous? Mukasa

Hello Mukasa, the SBC (Sensotronic Brake Control) unit is a Mercedes innovation which is designed to improve your car’s braking efficiency and safety, especially when braking in a corner or during slippery conditions.

It is designed with a micro-computer and hydraulic pump which rely on wheel speed sensors to monitor different wheel speeds and apply independent brake pressure to stabilise the car when braking on wet road surfaces or manoeuvering around sharp bends or corners.

In the event that SBC fails, a red warning light on the dashboard will advise you to visit the workshop. Total failure of the SBC will not only reduce braking efficiency during emergencies but may also lead to total loss of brakes or catastrophic brake failure.

The SBC unit on your car can fail due to failure to renew brake fluid on time using the correct service procedure and tools, electrical circuit failure or shutdown due to accumulation of the 300,000 brake excitation limit. The last reason is the common cause of failure.

Mercedes designed the SBC (2003-2005) to work for 300,000 brake excitations (kicks of the brake pedal). Once the limit is reached, it calls for replacement in order to maintain its efficiency. Models built after 2005 had an adjustment made to avoid this problem. You need to get a diagnostic check of your Mercedes SBC to determine what has caused its failure.