Yes, so you shouldn't drive it if you've misfuelled or you'll damage the engine. Putting petrol into a diesel tank causes more damage than diesel in a petrol car because diesel acts as a lubricant. Petrol does the opposite so it increases friction between parts in the diesel engine. The more petrol that's pumped through the diesel engine, the more damage it'll do. If there's a lot of damage, it could mean new fuel pumps, injectors, pipes, filters, fuel tank – or even a whole new engine.