A control system for a vehicle includes a CPU, a throttle sensor, a brake sensor, and fuel injectors. When the CPU detects a control failure of the throttle valve with a value detected by the throttle sensor, the CPU adjusts the output of the engine by controlling the fuel injectors such that the motorcycle runs with a previously set negative target acceleration. Also, when the CPU detects a brake operation by the driver with the brake sensor after the occurrence of the control failure, the CPU corrects the target acceleration such that the deceleration of the motorcycle becomes larger. Then, the CPU adjusts the output of the engine such that the motorcycle runs with the corrected target acceleration.