If tuning measures are taken in public road traffic, for which no TÜV test certificate according to § 19 StVZO is available, the license and the insurance cover of the vehicle will be extinguished.

All technical modifications to a vehicle must always be inspected from the traffic authorities. This is particularly the case for measures that increase performance. The legal basis for this is set forth in the German road traffic regulations (StVZO).

Already in 1996 we jobed out the first TÜV parts certificates according to § 19 StVZO. In total, nearly 600 TÜV parts certificates are available for more than 3,500 vehicle types. The expansion of this portfolio is ongoing.

In order to obtain TÜV part certification the following inspections must be carried out:

• An exhaust gas emissions measurement in accordance with EU Directive 70/220 or 715/2007/EWG
• Vehicle noise emission measurement in accordance with EU Directive 70/157/EWG
• Engine power measurement in accordance with EU Directive 80/1269/EWG
• Top speed measurement in accordance with ECE Regulation no. 68

Unfortunately there are no TÜV certificates available for vehicles with truck license. The test procedure for trucks requires that the engine has to be removed for exhaust tests. This is not feasible due to the efforts and costs.

For changes to the original engine control unit software, called OBD or flashtuning, no TÜV parts may be issued according to § 19 StVZO, since the software, which has been re-recorded on the engine control unit, is not a "part" in the sense of § 19 StVZO. These tuning measures are also explicitly excluded in the 715/2007 EEC (Euro 5 and 6 exhaust gas standard). In the case of software updates, these "tuning files" are again overwritten. The engine is after the update, back to the serial state.

So far, the exhaust gas behavior of engines are measured on a roller test stand in the laboratory, according to the directives 70/220 EEC and 715/2007 EEC, according to the NEDC cycle (New European Driving Cycle).

In the future, these measurements are to be carried out in accordance with the new WLTP (Worldwide Harmonized Light-Duty Vehicles Test Procedure) measurement method to exclude manipulations (test bench driving detection). These are no longer carried out on the roller test stand, but in real-life operation on the road.

The test is much more dynamic than the NED and is considered much more realistic than that. The consumption values and the corresponding CO2 emissions are usually much higher than with the NEDC. Since many factors such as temperature, wind speed, road conditions, etc. are to be taken into account during measurements on the road, the results of the measurements will be subject to higher measuring tolerances than in the NEFZ cycle.

Comparison of measurement methods WLTP (WLTC) and NEFZ (NEDC)

Origin: https://de.wikipedia.org/wiki/Fahrzyklus