Control system and control method for throttle valve driving apparatus

In the event that an abnormality is detected in a throttle valve driving apparatus, an upper limit value for a throttle valve opening is set according to a vehicle speed when a brake switch is not switched on. When the brake switch is on, the upper limit value is set at a predetermined idle opening. When the target opening which is calculated according to an accelerator pedal depression amount is larger than the upper limit value, the target opening is changed to the upper limit value.