Toyota's new TS050 HYBRID World Endurance Championship challenger ran for the first time yesterday at the Aragon circuit.
The all-new LMP1 prototype undertook its first laps in the hands of Toyota stalwart Stephane Sarrazin on Tuesday's first day of a test also attended by Sebastien Buemi and Mike Conway.
Toyota is running the new car alongside one of last year's TS040 HYBRIDs over the course of three days at the Spanish track.
A spokesman for the Toyota Motorsport GmbH squad told Autosport: "Everything went well, but that is all we can say at this stage."
Toyota is not releasing technical details of its latest LMP1 until a launch at Paul Ricard on March 24, the day before two-day WEC pre-season test begins at the French circuit.
It revealed in June that it was bringing forward development of a new petrol engine to replace its 3.7-litre normally-aspirated V8 in time for the 2016 season.
This means it has coincided with the introduction of a battery energy-storage system for its hybrid energy in place of the super-capacitors used since its WEC entry in 2012.
Toyota has talked openly about the new engine as a turbocharged unit and it is understood that it has the same V4 architecture as the engine that took Porsche to last year's WEC titles.
The Japanese manufacturer has confirmed that it will continue to recover energy from the rear axle as well as the front, rather than harvesting energy from the exhaust gases like Porsche.
Audi tested its all-new R18 e-tron quattro for the first time at Ricard in November, while Porsche ran some of the components, including the engine and hybrid system, that will race on its updated 919 Hybrid at Aragon in December.