System description Diagnosis · Whenthe ignition is switched on, the

911 Carrera (996) HBA diagnosis System description Diagnosis Whenthe ignition is switched on, the The HBAsystem is installed in vehicles with servomotors for HBAare set to the minimal Litronic headlights. position and subsequentlyreturned to the initial position. There is a fault in one or both motor The HBAsystem consists of the following circuits if the servomotors are not set to components: minimum position when the ignition is switched on. The angle sensors (axle position sensors) Angle sensor for HBA, rear, with linkage are faulty if the servomotors are not set to high-beamposition when high beam is activated. Angle sensor for HBA,front, with linkage Note: One stepper motor in each headlight When high beam is activated,the servomotors (servomotor for HBA) are set to high-beamposition only if the parking Control module light is switched on (terminal58). Note:Braking or acceleration, as well as loading, changesthe inclination of the vehicle and If there are faults in the motor circuit, the fault therefore the headlightrange. The HBAsystem memory will be updated only after the ignition already reacts to the above driving conditions has been switched off and then on again. After when the dipped beam is switched on, remedyingthe fault cause, switch the ignition off preventing oncoming traffic from being dazzled. and then on again and subsequentlyerase the Furthermore, the system ensures an ideal fault memory. headlightrange for the driver in all driving situations. If the fault cause has been remedied, faults in the sensor circuit will be automaticallydeleted The sensors at the front and rear axles measure when the ignition is switched off and then on the vehicle inclinationand forwards this value as again. 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 headlightsare adjusted to the appropriate position. The HBA system also functions with the high-beam setting. 94 92 Diagnosis/troubleshooting HBA 94 -D 9