EDK Throttle Position Feedback Signals
The EDK throttle plate position is monitored by two integrated potentiometers. The potentiometers provide DC voltage feedback signals as input to the ME 7.2 for throttle and idle control functions.
Feedback potentiometer 1 provides a signal ranging from 0.5V (LL) to 4.5V (VL),
Feedback potentiometer 2 simultaneously provides a signal ranging from 4.5V (LL) to 0.5V (VL).
Pot signal 1 is the primary signal, signal 2 is used as a plausibility cross-check through the total range of throttle plate movement.
If there is an open or short in signal 1, signal 2 is used as a temporary substitute providing failsafe operation (faults stored).
If the signals are not plausible, ME 7.2 determines intake air mass from the HFM signal (virtual Pot 3) and compares it with Pot 1 and Pot 2. The signal that is closest to virtual Pot 3 is then used and the other disregarded.
If ME 7.2 cannot calculate a plausible conclusion from the monitored pots (1 or 2 and virtual 3) the EDK motor is switched off and fuel injection cut out is activated (no failsafe operation possible).
Refer to EDK MONITORING AND FAILSAFE OPERATION .