Collision Prevention Assist Controller Unit, Component Description - GF30.30-D-3214H

MODEL 906.111/113/131/133/135/153/155/211/213/231/233/235/253/255/611/613/631/633/635/637/653/655/657/711/713/731/733/735 with CODE JA6 (COLLISION PREVENTION ASSIST) 

Courtesy of MERCEDES-BENZ USA

Location 

The COLLISION PREVENTION ASSIST control unit is located on the right next to the license plate number behind the front bumper. The bumper shields the COLLISION PREVENTION ASSIST control unit against external effects (for example dirt, ice or insects)

Task 

The COLLISION PREVENTION ASSIST control unit controls and regulates the following functions:

• COLLISION PREVENTION ASSIST
• BAS

From these arise the following individual tasks for the COLLISION PREVENTION ASSIST control unit:

• Read in input signals 
• Evaluation of the input signals 
• Transmission of output signals 

Read in input signals 

The following input signals are read in via the engine-CAN (CAN C):

• vehicle speed from the instrument cluster (A1)
• wheel rotation directions, RPM sensor at the front left (L6/1), RPM sensor at the front right (L6/2), RPM sensor at the rear left (L6/3) and RPM sensor at the rear right (L6/4) from the ESP control unit® (N30/4)
• steering wheel angle, steering angle sensor (N80b1) from the steering column tube module (MRM) control unit (N80)
• enable status
• status of "circuit 61 ON" (engine runs)

Evaluation of the input signals 

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

Transmission of output signals 

The following output signals are transmitted by the COLLISION PREVENTION ASSIST control unit via the engine-CAN:

• Increase/reduce the braking torque at the ESP control unit®.
• Requests for emission of static warning messages in instrument cluster:
  • The static warning message takes place purely optically. If the distance to the vehicle immediately ahead is not achieved for t = 0.8 s and has remained at this critical distance for t > 3 s, the COLLISION PREVENTION ASSIST control unit sends the request to issue the warning via the engine-CAN to the IC. The instrument cluster reacts by actuating the COLLISION PREVENTION ASSIST (A1e52) warning lamp.
• Requests for emission of collision critical warning messages in instrument cluster:
  • The collision critical warning message occurs both optically and acoustically. Of a moving obstacle is assessed as accident critical (a collision will occur within t < 2.6 s) the COLLISION PREVENTION ASSIST control unit transmits the request to issue the warning via the engine-CAN to the IC. The instrument cluster reacts by actuating the COLLISION PREVENTION ASSIST warning lamp and the warning buzzer (A1h1).

Body 

There is a radar sensor and a controller unit integrated in the COLLISION PREVENTION ASSIST control unit.

A 24 GHz radar sensor is installed as a radar sensor which operates according to the pulse Doppler principle for independent measurement of distances and speeds which has a detection range of the radar sensor of s = 0 to 80 m for a detection angle of ∠ = 18° +/-8°.

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