Extracting and changing coding
Note. Communication with the HBA gas discharge lamp control unit can only be established once ignition and dipped beam are switched on. Each Bi-Xenon headlight, left and right, has its own HBA (Xenon) gas discharge lamp control unit. These can be read out and coded separately. Following replacement of the control unit(s) for the gas discharge lamp, always perform a drive link test on the HBA servomotor to check that the correct headlight is reacting (correct side) Before troubleshooting, always read out the fault memory of the other control unit for the gas discharge lamp, left or right, in order to determine whether faults are related. The power supply and the shift function come from the vehicle electrical system control unit. The fault memory of the vehicle electrical system control unit should be read out first before troubleshooting. If it is not possible to communicate with the (HBA) control unit for the gas discharge lamp in the headlight, this may be caused by incorrect coding, e. g. both headlights are coded on one side. Remedy: Remove one headlight and restart connection setup using the Tester. Code control unit correctly. In vehicles with level adjustment (air springs), the signal for the vehicle position is received via the level adjustment system control unit. This has four angle sensors for compression. In vehicles without level adjustment (steel springs), two angle sensors - front left and rear left - are installed for compression detection.
Under menu item
- Special functions
- HBA left or right
Coding can be read out indicating which equipment features are activated and which are not.
The following equipment features can be set
- Control unit, right
- Control unit, left
- Right control unit in conjunction with level adjustment system
- Left control unit in conjunction with level control system
Read out the fault memory again and erase as necessary.
If faults are still present, then continue in accordance with Rep.-Gr. 9457 Technical Manual, Diagnosis .
| CAUTION | Coding: make sure that the headlight system is coded correctly in the vehicle electrical system control unit (always code Xenon headlights as well). |
> Incorrect coding in the vehicle electrical system control unit can damage the control unit for the HBA gas discharge lamp.
1. Install main headlight and perform function test > 941519 Removing and installing main headlight - "installing" .
1. Switch off light.
2. Remove main headlight. > 941519 Removing and installing main headlight - "Removing" .