ACC / LRR Sensor Setting

ACC/LRR Sensor Setting

The setting of the ACC or long range sensor (LRR = Long Range Radar) is required if:
- an calibration fault has been saved in the fault memory
- the sensor has been removed or installed
- a new sensor has been installed

Preconditions
The sensor setting must be made on a special setting bay with guide rails firmly fixed to the floor.
The sensor may only be set using the special tools and test equipment approved by BMW.
All test equipment must be in a satisfactory condition and must show no signs of damage.
Attention should be paid to ensuring that the guide rail and the neighboring area are free of dirt and other objects.

Notes on setting
The function of the ACC system depends greatly on the exact setting of the sensor. This is why the calibration must be made with the utmost care in line with the instructions in the test module.

Pay attention to the following points:
- The vehicle must not be damaged in the area of the ACC / LRR sensor.
- The bracket for the sensor must not be deformed.
- The sensor must be firmly snapped into place in the bracket.
- Before starting the setting procedure, connect the charger and diagnostic head.
- Check the air pressure in the tires and adjust if necessary.
- Engage the parking brake.
- Ensure that the vehicle is unevenly loaded.
- Remove the caps of the rim locks.
- When attaching the quick-action clamp, make sure that all the magnetic elements are correctly placed on the wheel bolts.
- During the setting procedure, under no circumstances may you lean on the vehicle.
- Never look directly into the light source of the laser pointer!

Adjusting screws
The ACC / LRR sensor is set by means of two adjusting screws.







Sensor ACC2
1: Adjusting screw, top left, for vertical calibration
2: Adjusting screw, bottom right, for horizontal calibration
3: Fixed mount







LRR Long Range Radar
1: Adjusting screw, bottom left, for horizontal calibration
2: Adjusting screw, top right, for vertical calibration
3: Fixed mount

Direction of rotation and angle of rotation
During the calibration of the sensor, the direction and angle of rotation are specified in the test module. These values apply only to a narrow range (linear range) close to the correct setting value. If the specified values in the test module mean that no rapid approximation (approx. 7 correction loops) of the nominal value is possible, the sensor is located
outside the linear range. In these cases, remove the sensor and make a rough setting of the sensor.

NOTE: the setting values for the rough setting are shown in the help document for the service function in the chapter "Used radar sensors".

Notes on setting the measuring device







Setting the slit diaphragm
Place the slit diaphragm and housing of the laser pointer exactly vertical. Set the height of the slit diaphragm in such a way that the light of the laser pointer passes exactly through the slit diaphragm.







Vertical mirror calibration
Scale and knurled wheel for the vertical mirror calibration.







Horizontal mirror calibration
Scale and retaining screw for the horizontal mirror calibration.







Folding device for mirror
Folding device to fold the mirror forwards and back. The illustration shows the mirror in the "rear" position (mirror folded away from vehicle).