The Venezuelan set the best time of the day in 1m24.871 and completed 102 laps of the Spanish circuit.
|Kimi Raikkonen, Ferrari (Photo: WRI2)|
Nico Rosberg, driving the Mercedes AMG W05 fitted a trumpet-shape object on the end of the car's exhaust during the morning's running in Spain set the second fastest time in 1m25.805.
Ferrari's Kimi Raikkonen was third quickest ahead of Esteban Gutierrez in the Ferrari-powered Sauber.
Williams' development driver Susie Wolff made her second appearance at a group F1 test, following her debut at last year's Young Driver Test, in the FW36.
|Susie Wolff, Williams (Photo: WRI2)|
Although a spin compromised her morning's running, Wolff recovered to complete 55 laps in a best time of 1m27.280, which was good enough for fifth place on the timesheet.
Jules Bianchi was 6th in the Marussia. However, mechanical gremlins kept the Frenchman in the garage for several hours.
Sebastian Vettel was 7th in the Red Bull RB10, one place ahead of Sahara Force India test driver Daniel Juncadella had an off at Turn Four which damaged the VJM07's front-wing.
|Stoffel Vandoorne, McLaren (Photo: WRI2)|
McLaren, meanwhile, gave an F1 test debut to their protégé Stoffel Vandoorne as the Woking team (and Sahara Force India) took over Pirelli tire development work.
Toro Rosso though ran into more sustained trouble, Daniil Kvyat completing just 21 laps as the STR9 broke down on track.
Barcelona in-season test*, day 2, Wednesday May 14:
1 Pastor Maldonado Lotus 1m24.871s 102 laps
2 Nico Rosberg Mercedes 1m25.805s 102
3 Kimi Raikkonen Ferrari 1m26.480s 94
4 Esteban Gutierrez Sauber 1m26.972s 85
5 Susie Wolff Williams 1m27.280s 55
6 Jules Bianchi Marussia 1m27.718s 55
7 Sebastian Vettel Red Bull Racing 1m27.973s 73
8 Daniel Juncadella Sahara Force India 1m28.278s 91
9 Stoffel Vandoorne McLaren 1m28.441s 136
10 Daniil Kvyat Toro Rosso 1m28.910s 21