The two Toyota GR010 HYBRIDs locked out the top two positions during Wednesday afternoon's three-hour session, with Brendon Hartley setting the pace aboard the #8 car on a 3m27.742s.
That was almost two seconds up on the best time set in Sunday's official test day.
It was the sister #7 Toyota that led the way for most of the session, as Jose Maria Lopez punched in a 3m28.290s early on, going a tenth faster than Loic Duval in the leading Peugeot 9X8.
That was then bettered by Kamui Kobayashi, who lowered the bar to a 3m27.875s when the session was resumed following a red flag prompted by a crash at Tertre Rouge involving the #777 D'station Racing Aston Martin Vantage and the #13 TDS Racing-run Tower Motorsports LMP2.
Casper Stevenson had already suffered an off in the D'station car and was stranded in the middle of the circuit when Steven Thomas slammed into the side of the stricken Aston, leaving both cars badly damaged. The session was resumed after a 35-minute delay.
Hartley made his improvement with 23 minutes left on the clock to make it a Toyota 1-2, 0.133s ahead of Kobayashi, before the session was stopped for a second time with four minutes to go.
That was caused by another crash at Tertre Rouge, this time for the solo Corvette C8.R of Nico Varrone.
Source: Autosport