COLLISION PREVENTION ASSIST controller unit, component description - GF30.30-P-3214FLM

MODEL 212 as of model year 2014 up to model year 2015 with CODE 258 (Collision Prevention Assist) 

MODEL 212 as of model year 2015 with CODE 258 (COLLISION PREVENTION ASSIST PLUS) 

Fig 1: Collision Prevention Assist Controller Unit

Courtesy of MERCEDES-BENZ USA

Location 

The COLLISION PREVENTION ASSIST controller unit is located behind the front brand emblem.

Task 

The COLLISION PREVENTION ASSIST controller unit detects obstacles and vehicles moving immediately ahead and warns the driver about a possible collision.

If the COLLISION PREVENTION ASSIST controller unit detects a risk of collision, it initiates autonomous braking.

This means that the COLLISION PREVENTION ASSIST controller unit has the following individual tasks:

• Reading in input factors 
• Evaluation of input factors 
• Transmission of initial parameters 

Reading in input factors 

The input factors are read in via the following connection:

• Chassis CAN 1 (CAN E1) 

Chassis CAN 1 

The COLLISION PREVENTION ASSIST controller unit receives the following input factors via the chassis CAN 1:

• Wheel speeds and wheel rotation direction
• Steering angle
• Driver request via menu settings in the instrument cluster (A1)

The resulting functions are described in the respective function descriptions (see also block diagram or function schematic).

Evaluation of input factors 

The input factors are evaluated by the microprocessor and the corresponding components are actuated.

Transmission of initial parameters 

The initial parameters are sent via the following connection:

• Chassis CAN 1 

Chassis CAN 1 

The COLLISION PREVENTION ASSIST controller unit transmits the following starting data via the chassis CAN 1:

• Requests to output optical and acoustic warning messages in instrument cluster
• Requirements for initiating PRE-SAFE® measures
• Request to initiate a brake application

The functions that use these signals are described in the individual function descriptions (see block diagram or function schematic).

Body 

The COLLISION PREVENTION ASSIST controller unit includes the following components:

• Radar sensor
• Control unit

Properties of the radar sensor:

• Detection range of the radar sensor s = 0 to 80 m for a detection angle of = 18° +/-8°
• 25 GHz radar sensor operating on the pulse Doppler principle for independent measurement of distance and speed

The COLLISION PREVENTION ASSIST controller unit must be newly adjusted after exchange (e.g. after an accident repair) using the integrated "service adjustment mode".