AWE Tuning Exhaust Valve Simulator/BracketPerfect Fit. If you are planning to install a Axle Back or Cat Back Exhaust System that is not designed to be used on an Active Exhaust equipped Mustang, you will get a Check Engine Light due to the factory Active Valve not function properly. By installing this AWE Active Exhaust Valve Motor Bracket on your Mustang, this will basically trick the ECU to think that the Active Exhaust Valve Actuators is working properly, but when in reality the exhaust