An active air flap apparatus for a vehicle may include a drive flap positional sensor connected with a drive shaft connecting an actuator and a drive flap and detecting a rotational angle of the drive flap, a driven flap pivotally connected with the drive flap through a link mechanism, a driven flap positional sensor connected with a driven shaft pivotally connected with the link member and detecting a rotational angle of the driven flap, and a controller determining whether the drive flap positional sensor, the driven flap positional sensor, a motor of the actuator, and the link member may be defective by monitoring a feedback voltage value of the drive flap positional sensor, a feedback voltage value of the driven flap positional sensor, and a current applied to the motor of the actuator.