AbgassystemÜberwachung

AbgassystemÜberwachung, often abbreviated as AU, is a mandatory vehicle inspection in Germany designed to verify that a vehicle's exhaust system complies with environmental regulations. The primary goal of AU is to reduce harmful emissions released into the atmosphere, thereby contributing to cleaner air and public health.

During an AU inspection, a technician uses specialized equipment to measure the levels of various pollutants present in the vehicle's exhaust gases. These typically include carbon monoxide (CO), hydrocarbons (HC), nitrogen oxides (NOx), and particulate matter (PM), depending on the vehicle's age and fuel type. The measured values are compared against legally defined emission limits.

If the vehicle's emissions exceed these limits, it fails the AU inspection. In such cases, the owner must have the necessary repairs or adjustments made to the exhaust system, which may include replacing catalytic converters, oxygen sensors, or addressing other engine-related issues that impact emissions. Once repairs are completed, a re-inspection is required.

Successfully passing the AU inspection is a prerequisite for obtaining or renewing the vehicle's general inspection certificate (Hauptuntersuchung, HU). Vehicles that do not have a valid AU certificate are not permitted to be driven on public roads. The AU requirement applies to all motor vehicles, including cars, motorcycles, and commercial vehicles, with specific standards tailored to different vehicle categories and emission control technologies.