Nick Heidfeld will start from the back of the grid at the Singapore Grand Prix, his BMW Sauber team confirmed on Sunday.
The German had qualified in eighth position but he will take the start from the pitlane after his car was found to be underweight after qualifying.
"When Nick Heidfeld's car was weighed after qualifying we found out we were slightly under the minimum weight," a BMW spokesperson said. "We have been investigating this and have found that the wrong ballast weights were fitted to the car.
"We have reported our findings to the FIA. As a consequence Nick will start the Singapore Grand Prix from the pitlane.
"As we found ourselves in this situation, the team also decided to change both the engine and gearbox."