Blind Spot Monitoring Radar Sensor Controller Unit, Basic Function - GF54.71-P-9891A

Model All (CAR) with code 234 (Blind Spot Assist) except code 233 (Adaptive cruise control Plus (DISTRONIC PLUS)) 

Example illustration of integrated rear outer radar sensor 

Courtesy of MERCEDES-BENZ USA

Overview 

This document contains information on:

• General 
• Function 

General 

The radar sensor transmits bundled electromagnetic waves as so-called primary signals. Objects in the detection range of radar sensor reflect these electromagnetic waves.

Function 

The radar sensor receives the reflected electromagnetic waves (secondary signals) and evaluates them according to various criteria. From this, various information is obtained about the objects.

• Angle or direction to the object
• Distance to the object
• Speed differential

The outer rear radar sensors are connected via the peripherals CAN (CAN PER) to the network architecture of the vehicle.

The outer rear radar sensors operate according to the master/slave principle. The master or slave function can be determined via the connector coding. The master function is defined for the right rear radar sensor. This means that the left rear radar sensor transmits its information via the peripherals CAN to the right rear radar sensor. The right rear radar sensor evaluates the information from both rear radar sensors and transmits corresponding requests and data via the peripherals CAN.