Italian Jarno Trulli's Renault failed an inspection after finishing fourth in today’s Monaco Grand Prix and the results from that position downwards are likely to stay provisional until Tuesday.
The International Automobile Federation (FIA) said in a statement that "all cars save for car number 14 (Jarno Trulli) have been found in conformity with the F1 technical regulations."
The problem concerns electronic software and an FIA spokeswoman said a further, more detailed investigation would be necessary.
The top three positions -- winner David Coulthard for McLaren, Michael Schumacher for Ferrari and Ralf Schumacher for Williams -- were confirmed as official.
If Trulli were to be excluded, that would move Italian Giancarlo Fisichella up to fourth place for Jordan, Heinz-Harald Frentzen to fifth for Arrows and Brazilian Rubens Barrichello into sixth for Ferrari.
The extra point would also allow Arrows to move ahead of Minardi and Toyota as the eighth-placed team.