Lewis Hamilton's first day behind the wheel of his Mercedes resulted in a crash into a tyre barrier.
Team-mate Nico Rosberg yesterday completed just 14 laps following an electrical fault which led to a small, short fire and the replacement of the wiring loom on the W02.
Following lengthy repairs by the team, Hamilton was at least able to make his debut on time for the second day of the opening pre-season test at the Circuito de Jerez.
But after 15 laps, the 28-year-old locked up at the turn-six hairpin known as 'Dry Sack' at 170mph before ploughing through a wide expanse of gravel and eventually pushing his front wing into the tyres.
Mercedes later diagnosed the issue on Hamilton's car as a loss of rear brake pressure.
A team spokesperson said; "The front brakes enabled him to slow the car but he couldn't avoid the barrier.
"There is obvious damage to the front wing and nose; we are checking the car over now. Lewis himself is fine."
Given the tyre marks on the asphalt on approach to the corner, and the fact Hamilton's car simply careered straight on for 70 metres, the early diagnosis is a fault to the front suspension.
Hamilton emerged unscathed from a car that was soon recovered from the barrier, covered with a black tarpaulin and craned on to the back of a flatbed truck before being taken back to the garage.
It means Mercedes face another investigation into their second successive testing incident, and with more repairs required, it remains to be seen whether Hamilton will make it back out on track later today.