Non-glare high-beam assistant: Diagnosis

The exterior lighting must be set to the "diagnostic mode" as a condition for carrying out various diagnosis orders. For example, the "diagnostic mode" is required for the following diagnosis orders:

• Reading out relevant bus signals while the vehicle is stationary
  • Speed
  • Yaw rate
  • Steering angle
• Analysis of switch-on conditions
  • Status of rain-light-solar-condensation sensor.
  • Status of non-glare high-beam assistant
  • Status of light switch

Missing or implausible bus signals will be stored as faults.

The types of faults are stored in the headlight driver module. The footwell module (FRM) or the front electronics module (FEM) or the body domain controller (BDC) enables access to the headlight driver module.

General notes 

Monitoring of light source 

When switched on, all exterior light sources are monitored by the footwell module (FRM) or front electronics module (FEM) or body domain controller (BDC). The monitoring starts at terminal 15 ON.

Hot monitoring with light ON 

Hot monitoring is based on the current measurement. The power consumption readings assist in detection of short and open circuits. For example, if the power consumption of the gas discharge bulb cannot be measured while the xenon light is switched on, the footwell module (FRM) or front electronics module (FEM) or body domain controller (BDC) detects a faulty xenon light. The system cancels the activation signal to the affected xenon light and a Check Control message appears in the instrument panel's display panel.

The monitoring function also embraces the light-emitting diodes in the exterior lighting. This function relies on monitoring of power consumption. Failure of light-emitting diodes is also indicated as a Check Control message in the instrument panel (KOMBI).

We can assume no liability for printing errors or inaccuracies in this document and reserve the right to introduce technical modifications at any time.