On Board Diagnostic (OBD), function

The automatic vertical headlight aim control system control module is controlled by an internal microprocessor with On Board Diagnostic (OBD) capability. If malfunctions occur in monitored sensors and components, Diagnostic Trouble Codes (DTC) will be stored in memory.

Before performing any troubleshooting or inspection, always begin by checking for DTCs using the On Board Diagnostic (OBD) program. DTCs stored in memory are retrieved/checked with either the VAG 1551 scan tool or VAS 5051 in mode "Self Diagnosis". See AUTOMATIC VERTICAL HEADLIGHT AIM CONTROL, ON BOARD DIAGNOSTIC (OBD) .

Where applicable, also use VAS 5051 tester in mode "Guided Fault Finding".