SBC additional functions, function

The Sensotronic Brake Control (SBC) carries out various additional functions (multiple value functions) of the ESP control unit (N47-5) which serve to make life easier for the driver or to assist the readiness for braking.

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Precharging function

This permanently active function assists the readiness for braking by immediately and briefly applying the brake linings.

The ESP control unit detects the introduction of an emergency stop by the rapid release of the accelerator pedal and comparison with stored data.

The ESP control unit actuates the SBC control unit (A7/3n1) which overcomes the clearance in a timely manner by precharging the brake system briefly and shortens the pressure buildup of the brake system. If the driver then depresses the brake, then a spontaneous response of the brake resultant shorter stopping distance is achieved. Precharging itself is carried out with a pressure of up to 3 bar. The release speed of the accelerator pedal is evaluated driver-specific.

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Dry braking function

This function assists the readiness for braking with wet brake disks by regular, brief dry braking.

Wet conditions are recognized via the activation of the windshield wipers. The ESP control unit receives the information on the windshield wiper frequency from the driver-side SAM control unit with fuse and relay module (N10/1) via the interior CAN (CAN-B). It actuates the SBC control unit (A7/3n1) depending on the thickness of the deposits.

Dry braking is carried out every 600 windshield wiper cycles, depending on the thickness of the deposits this corresponds to a time of approx. 7 to 14 minutes, provided that the driver does not brake in the meantime. If the driver brakes, the counter status is reset by 200 windshield cycles. When 600 windshield wiper cycles are achieved, dry braking is only carried out if the vehicle speed is between 30 and 200 km/h and the lateral acceleration is below
1 m/s2. Dry braking is carried out with a brake pressure of approx.1.5 bar for approx 3 seconds.

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SBC-Hold function

This function makes available a permanently adjusted brake pressure at the request of the driver. It serves to make life easier for the driver when maneuvering, starting off on a hill or during a prolonged stop.

Function requirements:

 Circuit 61 "On" (engine running)

 Speed v = 0 km/h

 Parking brake released

 The driver's door and engine hood are closed

 Selector lever on D, R or N

The SBC-Hold function is activated by operating the service brake when stationary with a certain pressure on the brake pedal. The activation is displayed permanently in the multifunction display (A1p13) in the instrument cluster (A1) and the vehicle is held without the service brake having to be operated.

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SBC-Hold is switched off automatically:

 when the accelerator pedal is pressed

 when the parking brake is operated

 the brake pedal is operated with a certain pressure until the SBC-Hold display goes out in the multifunction display

 the selector lever is shifted into position P

A warning tone sounds in the multifunction display when SBC-Hold is activated and when:

 the driver's door is open

 Engine hood is open

 circuit 61 "OFF"

 System fault

In addition horns sound when the SBC Hold is activated as a reminder for the driver that he must switch off the SBC-Hold and secure the vehicle:

 as soon as the hood is opened

 when the driver's door is opened and circuit 61 is "OFF"

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SBC-Stop function

The SBC-Stop function is no longer available on vehicles as of 01.06.04

Softstop function

The softstop function is no longer available on vehicles as of 01.06.04