Like Lotus, Williams endured a second successive day of frustration in Spain after mechanical issues and an accident meant Pastor Maldonado was restricted to fewer laps than anyone else at Jerez.
The Venezuelan had lost a large chunk of time after the team was forced to rebuild the KERS unit on his car as a precaution after a warning light came on during the morning.
However, just two laps after leaving the pits to resume his programme, the GP2 title winner crashed into the barriers at turn four, damaging the car and putting him out of action for the remainder of the day.
Maldonado now hands the car to team-mate Rubens Barrichello for the remaining two days of the test.
“Today started well, then late morning we had a warning message on the KERS battery,” technical director Sam Michael said. “That required us to strip the battery to check if there was a problem or if we just had a sensor error - fortunately it was the latter. It cost us 3½ hours though.
“Despite that, we made some really useful progress understanding the car's aero characteristics with the setup changes we ran in the morning. We started this afternoon with a long run but went off at T4, the high speed left hander.”
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