WLTC, or the "Worldwide Harmonized Light Vehicles Test Cycle," is a chassis dynamometer test used to determine emissions and fuel consumption of light vehicles. It is also a crucial component of the WLTP test procedure. WLTC combined fuel consumption refers to the fuel consumption value measured for pure fuel or hybrid light vehicles under the WLTP test procedure during the WLTC cycle's comprehensive conditions. This metric allows consumers to objectively understand and compare the fuel efficiency levels of different vehicles. WLTC combined fuel consumption will gradually replace the previously widely adopted NEDC fuel consumption figures.

What is the WLTP Test Procedure?
WLTP (Worldwide Harmonized Light Vehicles Test Procedure) is a globally unified vehicle testing standard used to determine pollutant levels, CO₂ emissions, and fuel consumption of traditional and hybrid vehicles, as well as the pure electric driving range of pure electric and hybrid vehicles.
This new protocol is Appendix 15 of the "Global Technical Regulations" agreement adopted by the United Nations Economic Commission for Europe's (UNECE) Inland Transport Committee in 1998. The agreement has been approved by China, Japan, the United States, and the European Union. The WLTP standard replaces the previous New European Driving Cycle (NEDC) as the certification test procedure for European vehicles.
The final version of the WLTP was released in 2015. It allows for better alignment between laboratory-tested estimated fuel consumption and emission levels and actual measurements under real-world driving conditions.
Carbon emission requirements are unavoidable for major automakers globally. The WLTP test procedure helps the automotive industry establish a level playing field in the global market. Besides EU countries, WLTP has also been adopted by countries like India, South Korea, and Japan. Additionally, WLTP is linked to EU Regulation (EC) 2009/443 to assist in verifying manufacturers' corporate weighted average fuel consumption and CO₂ emissions.