Sho Tsuboi set the pace in the closing moments of the morning session that was disrupted by no fewer than five red flags at the wheel of Cerumo's #14 car, setting a best time of 1m18.123s and leading a Toyota 1-2 ahead of TOM'S driver Yuhi Sekiguchi.
That turned out to be the day's quickest time, as Hiroaki Ishiura's best effort in the afternoon session of 1m18.193s in the sister #38 machine fell just 0.070s short.
However, Bertrand Baguette's Saturday benchmark of 1m17.850s, set at the wheel of the Real Racing Honda NSX-GT, was not bettered.
Sekiguchi's time in the #36 TOM'S Supra in the morning session was good enough for third overall behind the two Cerumo-run cars, with Baguette once again finishing up as top Honda driver in the #17 machine, just a further 0.007s back.
#19 WedsSport ADVAN GR Supra with crash damage
Kunimoto was taken to the medical centre as a precaution but escaped injury.
In GT300, the Cars Dream Tokai28 Lotus Evora MC of Hiroki Katoh set the pace overall with a best effort of 1m25.595s in the morning session.
Second overall was the quickest car in the afternoon, the works-entered Subaru BRZ R&D Sport on a 1m25.773s, followed by the #31 apr Toyota Prius PHV GR Sport, the Team Hitotsuyama Audi R8 LMS and the Tomei Sports Nissan GT-R NISMO GT3.
GT500 test results:
Nissan test car
Tyre key: B = Bridgestone, D = Dunlop, M = Michelin, Y = Yokohama