A Hauptuntersuchung is not a mystery and not a shakedown — it is a documented checklist anchored in §29 StVZO. This guide walks you through what every inspector looks at, how much it actually costs in 2026, and the small preparations that turn a worrying morning into a short, routine appointment.

Every passenger car in Germany goes through the same ritual at regular intervals. The TÜV Report 2026 found 21.5% of vehicles had significant or dangerous defects, based on data from 9.5 million inspections at TÜV organisations between July 2024 and June 2025 (it does not cover all HUs). A bit of preparation moves you into the other 78.5%.

What the HU actually is (and is not)

The Hauptuntersuchung is a mandatory periodic vehicle inspection defined by §29 of the Straßenverkehrs-Zulassungs-Ordnung (StVZO). It is not a maintenance service — no oil change, no filter replacement happens at a TÜV station. An inspector looks at your car, decides whether it is legal to drive on German roads for the next two years, and assigns a sticker. The HU is carried out by state-recognised organisations: mainly the TÜV companies (TÜV Nord, TÜV Süd, TÜV Rheinland and others), DEKRA, GTÜ, KÜS and FSP.

When is your vehicle due for the next inspection?

A new passenger car gets its first HU 36 months after first registration. Every subsequent inspection is required every two years. The coloured Prüfplakette on the rear licence plate, between the district code and the letters and numbers (next to the registration seal), tells you when the next one is due: the number at the top is the month, the middle shows the year, and the colour follows a six-year cycle (2026 blue, 2027 yellow, 2028 brown). The HU is due by the end of the month shown. There is no legal grace period, but the fine only starts once you are more than two months overdue: €15 (more than 2 up to 4 months late), €25 (more than 4 up to 8 months), €60 plus one Flensburg point (more than 8 months). More than two months overdue also means an extended check (Ergänzungsuntersuchung) with a 20% fee surcharge.

Who can inspect — TÜV, DEKRA, GTÜ, KÜS compared

ORGANISATION NOTES
TÜV companies (TÜV Süd, TÜV Nord, TÜV Rheinland, TÜV Hessen and others) Technische Prüfstellen; regional companies, each with its own stations
DEKRA Technische Prüfstelle in the eastern Länder; runs its own stations
GTÜ Recognised monitoring organisation; tests in workshops and at its own sites
KÜS Recognised monitoring organisation; tests in workshops and at its own sites
FSP Recognised monitoring organisation

According to ADAC, the average price for HU+AU on a passenger car is about €163 in 2026; prices differ by organisation and Bundesland, so compare locally.

How defects are classified: the Mängelbericht system

CATEGORY (GERMAN) ENGLISH PASS STICKER?
Geringe Mängel Minor defect Yes, but fix the defects without delay, at the latest within one month (no re-inspection)
Erhebliche Mängel Significant defect No
Gefährliche Mängel Dangerous defect No
Verkehrsunsicher Road-unsafe No (sticker removed, authority informed, car must not be driven on public roads)

Source: Anlage VIII StVZO, Nummer 3.1.4. A fifth outcome is "ohne festgestellte Mängel" (no defects found).

The Abgasuntersuchung: emissions, OBD, and why batteries matter

If your battery was recently disconnected — because you replaced it or a workshop reset the system — the OBD readiness monitors have not yet completed their self-test cycles. The inspector sees NOT READY and the AU cannot be completed. As a rule of thumb, drive about 30 km of mixed traffic the day before the appointment to complete the monitors.

Key takeaways

  • The Hauptuntersuchung is a statutory inspection under §29 StVZO — not a maintenance service.
  • New passenger cars: first HU at 36 months, then every 24 months.
  • Combined HU+AU for a passenger car costs around €160 on average in 2026 (ADAC).
  • Defects classified into four categories: geringe (minor, sticker issued, fix within one month), erhebliche (significant, fail), gefährliche (dangerous, fail), verkehrsunsicher (sticker removed, no driving), plus the fifth outcome ohne festgestellte Mängel.
  • The TÜV Report 2026 found 21.5% of inspected vehicles had significant or dangerous defects.
  • A disconnected battery or recent ECU reset prevents OBD readiness monitors from completing — as a rule of thumb, drive about 30 km the day before.
  • A failed HU is not a disaster: you have one month to fix serious defects and re-present the car with the inspection report for a re-inspection (about €30 according to ADAC). Miss the month or the report and you need a full new HU.

Sources & methodology

  • Anlage VIII and Anlage VIIIa StVZO — legal text.
  • TÜV Report 2026 — 9.5 million inspections analysed between July 2024 and June 2025.
  • ADAC — HU and AU costs 2026 (average price about €163).
  • ADAC — Hauptuntersuchung technical guide and fee overview.