The defending Champions are yet to have a trouble-free weekend when it comes to the Kinetic Energy Recovery System after both Sebastian Vettel and Mark Webber suffered problems in Australia, Malaysia and China.

However, the team are confident their difficulties with the hybrid system are in the past after making changes during the three-week break.

"Our KERS is fine," Marko told German tabloid Bild. "We tested it over Easter and made modifications."

Red Bull had problems with some cooling issues, but Marko insists it's "much cooler now" and will function properly at Istanbul Park.