4.26.1 Description
The Electronic Throttle Interface consists of 2 Pulse Width Modulation (PWM) output drives to control the throttle blade position, with 2 analogue signals for throttle position feedback. The 2 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.