we have a s300 turbo diesel. our car is equipped with drive by wire accelerator pedal. if we start the car, the engine will start without any hesitation. yet if we depress the accelerator pedal, nothing happens. no matter how long we depress the accelerator pedal, engine doesn't response, the engine will be on idle only. we replaced the accelerator pedal sensor & throttle actuator (located beside injection pump) yet the problem remains. we checked all the electrical wiring related to engine ECM, all is fine. what seems to be the problem? am i beyond help?