172 RENR5042-02 Troubleshooting Section g01122050 Illustration 91 Throttle position sensor with a knob Refer to Illustration 92. The sensor creates a Pulse Width Modulated (PWM) signal. The duty cycle varies with the throttle position. The signal has a low duty cycle when the throttle is at low idle. The signal has a high duty cycle when the throttle is at high idle. The Electronic Control Module (ECM) processes the signal in order to control the engine speed. g01122143 Illustration 92 Duty cycle versus throttle position The signal from the throttle position sensor has a specific frequency.
The frequency of the signal must be between 150 Hz and 1050 Hz or the ECM will activate a 091-08 diagnostic code.