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Making Technical Modifications to the Vehicle

Do you wish to carry out technical modifications to your vehicle or to a trailer? The operating permit can lapse as a result. You must provide proof that the technical modifications correspond to the regulations. The licensing authority can then issue you with a new operating permit for the vehicle.

Tip: Before carrying out an installation or modification, please contact an officially approved motor vehicle expert or an inspector from a technical monitoring organisation to see whether such changes will affect the vehicle's type-approval or whether it is possible for such changes to be approved in the first place, and whether the necessary approval can be obtained for a new type-approval.

Certain technical modifications must be inspected by the testing authority or an improved inspection organisation (TÜV, DEKRA, GTÜ, KÜS, GTS, FSP). You must then provide notification of these modifications to the licensing authority as quickly as possible. This includes:

  • changes to the vehicle category or the vehicle type or type of bodywork
  • changing the engine capacity, power output, type of fuel or source of energy
  • increasing the top speed depending on the type-approval
  • reducing the top speed depending on the type-approval if this has implications for the driver's licence or if it is relevant for the registration
  • making changes to the permissible axle loads, the overall weight, the drawbar- or trailer load
  • increasing the vehicle's dimensions- except for cars or motorcycles
  • changing the seating or standing capacity on coaches
  • any changes to the emissions or noise values where these changes have implications for motor vehicle tax or traffic bans

Note: Please clarify in advance whether you motor insurance covers the journey to the inspection organisation or testing authority.


The prerequisites for re-registering your vehicle after the technical modifications have been made are as follows:

  • You must prove that the modifications were made according to regulations. For this, you must have your vehicle inspected by officially approved motor vehicle experts. If you intend to present a general operating licence (Allgemeine Betriebserlaubnis, ABE) for vehicle parts or a parts inspection report to prove that the modifications have been carried out in compliance with regulations, you will require a confirmation of acceptance (Abnahmebestätigung). This does not apply to vehicle parts for which the general operating licence does not stipulate any acceptance obligation.
  • You may not have any unpaid charges or expenses from previous registration procedures. If you are more than 30 euros in arrears, the licensing authority is not permitted to register your vehicle until you have paid the outstanding amount. If the outstanding amount is less than 30 euros, the licensing authority may decide whether or not to register your vehicle despite the arrears.
  • You may not have vehicle tax arrears of five euros or more. Fines for late payment, interest and default penalties will be taken into account when the outstanding amount is calculated.
  • If you appoint a representative to register your vehicle, you must give this person written power of attorney. This must include a declaration of consent to the licensing authority giving your authorised representative information about outstanding fees and expenses. Your representative must present the written power of attorney and provide personal identification.

Responsible department

the registration authorities (Zulassungsbehörde), which are responsible for the principle residence of the owner (otherwise: company premises or location of the relevant subsidiary)

The registration authorities are

  • for an urban district (Stadtkreis): the city council (Stadtverwaltung)
  • for a rural district (Landkreis): the rural district office (Landratsamt)

Standard port

Geben Sie in der Ortswahl Ihren Hauptwohnsitz, den Betriebssitz oder Ort der Niederlassung ein.


You or your representative must report the technical modifications to the competent licensing authority and apply for a new operating licence.

Depending on the service provided by your licensing authority, you can download a form or use the online service for this purpose.

The licensing authority may ask you to show the vehicle.

Required documents

  • Valid identity card or passport
  • If you are being represented by a person with your written authorisation: in addition to the above,
    • valid identity card or passport of your representative
  • For underage vehicle owners: in addition to the above,
    • declaration of consent and identity documents of the legal custodian
  • For legal entities/companies:
  • The vehicle registration certificate (Zulassungsbescheinigung Teil I) (previously called "Fahrzeugschein")
  • The vehicle title (Zulassungsbescheinigung Teil II) (previously called "Fahrzeugbrief")
  • An expert's report or type-approval from the part manufacturer
  • Approval certificate from an authorised inspection organisation (TÜV, DEKRA, GTÜ, KÜS, GTS, FSP)
  • A valid inspection report from the last main inspection
    If your current inspection certificate for the emission inspection is dated before 1st January 2010, until your next main inspection you will have to prove that you have carried out the emission inspection by showing the inspection certificate separately.


The fees charged are based on the administrative costs (from 11,40 euros).

Note: The charges, which apply for obtaining technical approvals from authorised organisations, cannot be listed in detail here.

Release note

The German original version of this text was drafted in close cooperation with the relevant departments. The Verkehrsministerium released it on 16.08.2021. Only the German text is legally binding. The Federal State does not assume any liability for the translated texts.

In cases of doubt or if you have any questions or problems, please contact the relevant authorities directly.