Accelerator Pedal Position Sensor: Description and Operation

ACCELERATOR PEDAL POSITION (APP) SYSTEM DESCRIPTION




The accelerator pedal position (APP) system along with the vehicle electronics and components is used to calculate and control the amount of acceleration and deceleration via fuel injector control. This eliminates the need for a mechanical cable attachment from the accelerator pedal to a throttle body.

The APP system includes, but is not limited to, the following components :
- The accelerator pedal position (APP) sensor assembly
- The engine control module (ECM)

Accelerator Pedal Position (APP) Sensor
The accelerator pedal position (APP) sensor is mounted on the accelerator pedal control assembly. The sensor is made up of 3 individual sensors within one housing. Three separate signal, low reference, and 5-volt reference circuits are used in order to interface the accelerator pedal sensor assembly with the ECM. Each sensor has a unique functionality to determine pedal position. The ECM uses the APP sensor to determine the amount of acceleration or deceleration desired by the person driving the vehicle. The APP sensor 1 voltage should increase as the accelerator pedal is depressed, from below 1.0 volt at 0 pedal travel to above 2 volts at 100 percent pedal travel. APP sensor 2 voltage should decrease from above 4 volts at 0 pedal travel to below 3.0 volts at 100 percent pedal travel. APP sensor 3 voltage should decrease from above 3.8 volts at 0 percent pedal travel to below 3.3 volts at 100 percent pedal travel.