Mercedes will test Nico Rosberg's faulty gearbox in Friday practice for the Hungarian GP but are optimistic the championship leader will avoid a penalty.
The gearbox of the German's W07 car developed a fault towards the end of last week's British GP with the team's instructions to Rosberg about how to apply a fix triggering a post-race penalty.
If the unit has to be changed in Hungary then Rosberg would face a grid penalty.
However, the world champions will test it during practice at Hungaroring on Friday with a team spokesperson adding they were "optimistic" the gearbox will not need to be replaced.
Rosberg currently leads the Drivers' World Championship by a point.
"I'm feeling good, it's been a good season so far," the Mercedes driver said. "I think that we can all agree that up until now I have the best season of all the drivers."
Watch the Hungarian GP live on Sky Sports F1. The race starts at 1pm on Sunday, with build-up underway at 11:30am. Or watch the race without a contract for £6.99 on NOW TV.