AHL Control Unit Diagnostic Mode

For the following diagnostic operations, the AHL control unit must be set to diagnostic mode:

• Reading off relevant bus signals at a standstill shows whether or not the following signals are present:
  • Road speed
  • Yaw rate
  • Steering angle
• Check whether messages are received by the AHL control unit:
  • Check AHL control unit inputs
  • Check whether the AHL control unit is receiving any valid signals via the K CAN
• Check whether switch-on conditions for the adaptive headlights are satisfied:
  • Rain-light sensor status
  • Light switch status

Faults are stored as follows:

• Faults in the stepper motors etc. are fed to the AHL control unit by the stepper motor controllers (SMCs) and stored in the AHL control unit.
• The AHL control unit reports these faults in response to the status request (e.g. "communication with left-hand headlight failed").
• Missing bus signals and missing signals from components are stored in the AHL control unit.