Theory Of Operation

The Electronic Throttle Control (ETC) system uses two Throttle Position Sensors (TPS) to monitor the throttle blade position. TPS 1 and TPS 2 are located within the Throttle Body assembly. Each sensor has its own Signal circuit (TPS 1 or TPS 2). Both sensors share a common 5-Volt Reference circuit (Supply) and a common Sensor Ground. Each Signal circuit provides the Powertrain Control Module (PCM) with a signal voltage proportionate to throttle blade movement. Normally operating sensor signals are opposing to each other in the following manner:

• TPS 1  voltage starts low, approximately 0.5 volts at closed throttle,  and increases to approximately 4.5 volts at wide open throttle  .
• TPS 2  voltage starts high, approximately 4.3 volts at closed throttle,  and decreases to approximately 0.7 volts at wide open throttle  .