HBA Diagnosis

HBA diagnosis

System description
The HBA system is installed in vehicles with Litronic headlights.

The HBA system consists of the following components:
- The HBA system consists of the following components:
- Angle sensor for HBA, front, with linkage
- One stepper motor in each headlight (servomotor for HBA)
- Control module

Braking or acceleration, as well as loading, changes the inclination of the vehicle and therefore the headlight range. The HBA system already reacts to the above driving conditions when the dipped beam is switched on, preventing oncoming traffic from being dazzled. Furthermore, the system ensures an ideal headlight range for the driver in all driving situations.

The sensors at the front and rear axles measure the vehicle inclination and forwards this value as sensor signals to the control module, which carries out the further processing of the signals. If it should be necessary to change the headlight range, the stepper motors in the headlights are adjusted to the appropriate position. The HBA system also functions with the high-beam setting.

Diagnosis
When the ignition is switched on, the servomotors for HBA are set to the minimal position and subsequently returned to the initial position. There is a fault in one or both motor circuits if the servomotors are not set to minimum position when the ignition is switched on. The angle sensor (axle position sensors) are faulty if the servomotors are not set to high-beam position when high beam is activated (terminal 58 on).

NOTE:
- When high beam is activated, the servomotors are set to high-beam position only if the parking light is switched on (terminal 58).
- If there are faults in the motor circuit, the fault memory will be updated only after the ignition has been switched off and then on again. After remedying the fault cause, switch the ignition off and then on again and subsequently erase the fault memory.
- If the fault cause has been remedied, faults in the sensor circuit will be automatically deleted when the ignition is switched off and then on again.