GF82.10-P-3010RI Brake Light Actuation, Function

GF82.10-P-3010RI Brake Light Actuation, Function

Function requirements, brake light actuation, general
^ Circuit 15 On

Brake light actuation, general
Corresponding to the request the brake light actuation realizes a static or flashing actuation of the brake lights on the vehicle.

Brake light actuation is comprised of the following subfunctions:
^ Function sequence, static brake lights
^ Function sequence, adaptive brake lights

Function sequence, static brake lights
The circuit status of circuit 15 is made available on the interior CAN by the EIS [EZS] control unit (N73). Actuation of the service brake is defined by the brake light switch (S9/1). This is read in directly by the SBC control unit (A7/3n1). The SBC control unit sends the "brake lights On" request via the electro-hydraulic brake CAN to the ESP, SPS [PML] and BAS control unit (N47-5). From this, the request is transmitted via the engine compartment CAN and from there by the central gateway control unit (N93) via the interior CAN to the rear SAM control unit (N10/8).
In parallel with this, the "brake lights On" request (circuit 54) is passed on directly to the rear SAM control unit by the SBC control unit. This is intended to counteract the time delay in providing the request caused by transferring the signal over the various data buses.

The rear SAM control unit actuates the following components:
- Left brake light, taillight and parking light (E3e9)
- Right brake light, taillight and parking light (E4e9)
- Center high-mounted brake lamp (E21)

Additional function requirements, adaptive brake lights
^ Brake operated
^ Vehicle speed v > 50 km/h
^ Brake Assist system active or vehicle deceleration a > 7.5 m/s2

Function sequence, adaptive brake lights
Information on the vehicle speed is placed by the instrument cluster (A1) on the interior CAN.
In the event of danger braking, the ESP control unit transmits a corresponding signal on the engine compartment CAN. The central gateway control unit makes this signal available to the rear SAM control unit on the interior CAN. The rear SAM control unit receives all the relevant information, evaluates it and actuates the brake lights and the center high-mounted brake lamp at a frequency of f = 5 Hz for the duration of the signal (min. t = 1 s).

If the vehicle comes to a standstill after danger braking, the hazard warning flasher function is activated automatically.

The danger braking signal is reset if one of the following preconditions is met:
- Brake not operated
- Vehicle speed v < 10 km/h
- Vehicle deceleration a < 6.5 m/s2 (for at least t = 150 ms)