4.24.1 Description
The Electronic Throttle Interface consists of two Pulse Width Modulation (PWM) output drives to control the throttle blade position, with two analogue signals for throttle position feedback. The two position signals have positive linear characteristics. There are various diagnostic checks carried out on the throttle control system, all of which result in the illumination of the MIL if a fault is detected. The main checks are described below:
With the necessary enabling conditions satisfied:
- The difference between the actual throttle position and the requested position will be compared. If they differ by greater than a calibratable amount a failure judgment will be made.
- If the throttle blade position PWM is driven at 100% duty for greater than a calibratable period of time a failure judgment will be made.
- If an over current condition is detected by the throttle driver hardware for greater than a calibratable period of time a failure judgment will be made.
- If the input voltage to the ECM from either of the position sensors exceeds a defined threshold for greater than a calibratable period of time, a high failure judgment is made.
- If the input voltage to the ECM from either of the position sensors stays below a defined threshold for greater than a calibratable period of time, a low failure judgment is made.
- If the difference between the throttle angles reported by the two position sensors differs by greater than a calibratable value a failure judgment is made.