A vehicle has a drive unit driving wheels of a vehicle axle and braking the vehicle via a drive train in drag mode, an electronic control unit measuring actual wheel rotational speeds of the wheels, and a brake booster for reducing the actuating force at the brake pedal. A test unit is assigned to the electronic control unit and performs a plausibility check of the actual wheel rotational speeds in drag mode, wherein the test unit activates during the plausibility check the vehicle brake of one of the vehicle wheels and detects, from the rotational speed behavior of the wheel with a non-activated vehicle brake, whether the measured actual wheel rotational speeds correlate with the actual vehicle speed. A brake booster can be actuated by the test unit during the plausibility check in order to activate the vehicle brake.