Main-beam assistant diagnosis
The following general information about the main-beam assistant is provided for diagnosis:
- Visual inspection of the main-beam assistant
- Quick function check for the main-beam assistant
- Test procedure (test module) in BMW diagnosis system for main-beam assistant with the following steps:
- Checking main-beam assistant in diagnosis mode
- Resetting main-beam assistant to basic setting
- Adjusting the main-beam assistant
Make sure that the main-beam assistant's viewing window is clean.
All sensors for the main-beam assistant must be clean:
- Image sensor for main-beam assistant
- 2 photodiodes on the front and back of the interior mirror (the photodiodes measure the surrounding brightness)
Also make sure that these sensors are not obstructed by dangling objects or stickers.
The windscreen should be clean and should never have stickers attached.
If necessary, clean with a non-fluffy cloth and BMW window cleaner.
Visual inspection of main-beam assistant
In case of a malfunction in the main-beam assistant, first perform a visual inspection
If a fault should develop in the main-beam assistant, first conduct a visual inspection of the main-beam assistant.
This is because: The base of the interior mirror can be twisted by applying mechanical force (e.g. if the windscreen is cleaned incorrectly, etc.).
This will affect the operation of the main-beam assistant.
The illustration shows an interior mirror base twisted on the windscreen
- Screen-printed border on windscreen
- Mirror base twisted on windscreen
- The mirror base has been mechanically twisted in this direction.
The top right-hand edge of the mirror base protrudes beyond the screen-printed border.
The base of the interior mirror can be twisted by applying mechanical force.
If the mirror base is not centered in the screen-printed border, re-centralize the mirror base.
Quick function check for the main-beam assistant
Communication between the main-beam assistant and the light module is checked as follows:
- Place the vehicle in a darkened room.
- Switch on the ignition.
- Use a black cloth to cover up the rain-light sensor.
- Turn the light switch to position "A".
The green indicator light in the light switch comes on.
The automatic headlight control switches on the dipped headlights.
- Push the turn-signal/main-beam switch forward.
If the FLA indicator light comes on in the instrument cluster, communications between the control units are working correctly:
- Data transmission between the main-beam assistant and light module is working correctly.
- Data transmission between the light module and the instrument cluster is working correctly.
Test procedure for the main-beam assistant
The main-beam assistant is checked and adjusted as necessary with the test procedure (test module) in the BMW diagnosis system.
The test procedure for the main-beam assistant comprises 2 sections:
- Checking main-beam assistant in diagnosis mode
- Resetting main-beam assistant to basic setting
Checking main-beam assistant in diagnosis mode
The main-beam assistant can be subjected to an in-depth function test using the corresponding diagnosis mode set up in the BMW diagnosis system. Call up the test procedure "Check FLA".
The items required for the test are as follows:
- Clean, black cloth or other suitable item for covering the rain-light sensor
- Lamp for simulating oncoming traffic
The procedure for testing the main-beam assistant is as follows:
- Place the vehicle in a darkened room.
Make sure that there are no light sources or reflective objects in front of the vehicle.
- Switch on the ignition.
- Use a black cloth to cover up the rain-light sensor.
- Turn the light switch to position "A".
The green indicator light in the light switch comes on.
The automatic headlight control switches on the dipped headlights.
- Push the turn-signal/main-beam switch forward.
The FLA indicator light in the instrument cluster comes on.
Main-beam assistant test mode is started (in BMW diagnosis system test procedure).
The following situations are possible:
- The room is dark enough:
If the room is dark enough, the main-beam headlights will come on. The bi-xenon headlights are switched to full beam. The additional driving lights with the halogen bulbs are not switched on.
- If the room is not dark enough:
Hold your hand over the image sensor of the main-beam assistant.
The main-beam headlights should come on automatically after a few seconds.
If the main-beam headlights do not come on automatically, you might not have covered the main-beam assistant effectively enough to keep light from reaching the sensor.
- Increase the level of brightness in the room or use a lamp held in front of the car to direct a beam of light toward the main-beam assistant.
The main-beam headlights should switch off when the beam of light is in the field of vision of the main-beam assistant or when the room is bright enough.
- Remove the beam of light from the field of vision of the main-beam assistant. If necessary, use your hand to exclude light from the main-beam assistant. The main-beam headlights must come on again:
The bi-xenon headlights are switched to full beam.
The additional driving lights with the halogen bulbs are not switched on.
- If the main-beam headlights are not
switched on, the test procedure can send a switch-on recommendation to the light module (via the main-beam assistant).
The vehicle has to be prepared as described above, in order to ensure that the light module accepts the switch-on recommendation and switches on the main-beam headlights:
- Switch on the ignition.
- Use a black cloth to cover up the rain-light sensor.
- Turn the light switch to position "A".
The automatic headlight control switches on the dipped headlights.
The green indicator light in the light switch comes on.
- Push the turn-signal/main-beam switch forward.
The FLA indicator light in the instrument cluster must come on.
The main beam of the bi-xenon headlights are switched on when a switch-on recommendation is sent by means of a diagnosis command.
Resetting main-beam assistant to basic setting
Under the following conditions, it may be necessary to reset the main-beam assistant to basic setting:
- Windscreen or interior mirror has been exchanged.
Windscreen and interior mirror are in correct installation position (see "Visual inspection of main-beam assistant" above).
- Despite a lengthy journey at night of a straight section with easily recognizable road markings (drive straight for a distance of approx. 50 km: a relatively straight stretch accelerates the directional orientation).
The functional quality of the main-beam assistant is outside the system tolerance, even after the journey at night.
System tolerances are:
- Inclement weather conditions (e.g. fog)
- Poorly lighted road users (e.g. cyclists, pedestrians)
- Incorrectly interpreted road signs (e.g. the warning sign for a tight curve): Reflections from traffic signs may be incorrectly interpreted by the main-beam assistant as a vehicle driving ahead or as oncoming traffic.
- Driving over crests and/or through dips