Frentzen airs Sauber traction control fears

The Swiss team, which uses last year's Ferrari engines re-badged as Petronas, got both its cars home in the top six places with drivers Nick Heidfeld and Kimi Raikkonen sandwiching fifth-placed Frentzen.

Speaking on his website, Frentzen - who had been running third in the opening stages until being punted into a spin by Rubens Barrichello's Ferrari - couldn't understand why the Saubers were so difficult to pass.

"I got stuck behind Raikkonen's Sauber for a long time," he said. "I hoped I could get ahead in the pit stops, which I managed to do, by this time for sixth place.

"Heidfeld was the next car ahead and, even though I managed to catch him quite quickly, I knew passing him would be another matter. I don't know if traction control comes as a factory option with Ferrari engines, but every time I got close in a slower corner he would pull away under acceleration, which was strange as I could hear the engine misfiring!"

Both Saubers passed post-event scrutineering, and the FIA, the sport's governing body, is allowed access to engine management software at all times during a Grand Prix weekend. Traction control is banned until next month's Spanish Grand Prix.