The machine was towed back to the pits where mechanics spent much of the rain-affected day fixing what was believed to be an engine or gearbox problem.
"Reliability will be a key factor this year," said Schumacher. "It's not possible to know whether we can start winning right away and we won't really know that until we have tested against our competitors."
McLaren's troubles with their new MP4/12 continued when Mika Hakkinen was left stranded out on the track after completing just a handful of laps. David Coulthard had driven just three corners yesterday before encountering a drive problem.Reuse content