Accelerator Pedal Position Sensor: Description and Operation

The Accelerator Pedal Position (APP) sensor is mounted on the accelerator pedal assembly. The sensor is actually 3 individual APP sensors within 1 housing. Three separate signal, ground and 5.0 volt reference circuits are used to connect the APP sensor assembly and the Throttle Actuator Control (TAC) module. Each sensor has a unique functionality. The APP sensor 1 signal increases as the accelerator pedal is depressed, from below 1 volt at 0 percent pedal travel (pedal at rest) to above 2.0 volts at 100 percent pedal travel (pedal fully depressed). The APP sensor 2 signal decreases from above 4.0 volts at 0 percent pedal travel to below 2.9 volts at 100 percent pedal travel. The APP sensor 3 signal also decreases from above 3.8 volts at 0 percent pedal travel to below 3.1 volts at 100 percent pedal travel. Observe that the signal circuits for APP sensor 2 and APP sensor 3 are pulled up to 5.0 volts and the APP sensor 1 signal circuit is referenced to ground within the TAC Module.

When the PCM detects a malfunction with the APP sensor circuits, the following DTCs will set:
^ DTC P1125 APP System
^ DTC P1275 APP Sensor 1 Circuit
^ DTC P1276 APP Sensor 1 Circuit Performance
^ DTC P1280 APP Sensor 2 Circuit.
^ DTC P1281 APP Sensor 2 Circuit Performance
^ DTC P1285 APP Sensor 3 Circuit.
^ DTC P1286 APP Sensor 3 Circuit Performance

Accelerator Pedal Position (APP) Sensor:

The Accelerator Pedal Position (APP) sensor is mounted on the accelerator pedal assembly. The APP is actually 3 individual accelerator pedal position sensors within 1 housing. Three separate signal, ground and 5.0 volt reference circuits are used to connect the APP and the TAC module. The APP sensor 1 voltage should increase as the accelerator pedal is depressed, from below 1.0 volt at 0 percent pedal travel to above 2.0 volts at 100 percent pedal travel. APP sensor 2 voltage should decrease from above 4.0 volts at 0 percent pedal travel to below 2.9 volts at 100 percent pedal travel. APP sensor 3 voltage should decrease from above 3.8 volts at 0 percent pedal travel to below 3.1 volts at 100 percent pedal travel.