EMS Sensors (page 3 of 13)

ENGINE MANAGEMENT SYSTEM - SIEMENS

18-4-16 DESCRIPTION AND OPERATION

Accelerator Pedal Position (APP) Sensor – From 2003 Model Year

The APP sensor is attached to a bracket on the bulkhead. The throttle pedal is an integral part of the sensor. The 
pedal is attached to the sensor and rotates an internal pair of sensing elements. The pedal is also connected to two 
springs which provide a resistance force to pedal movement to improve feel and control.

The sensor comprises two resistance tracks (potentiometers) and two sliding contacts which are connected directly 
to the pedal. The sensor receives a 5V reference voltage from the ECM and outputs a linear voltage relative to the 
pedal position. The use of a pair of potentiometers ensures that an output signal is available should one of the tracks 
develop a fault.

APP Sensor Output Graph

A = Voltage

B = Pedal angle (degrees)

C = Full throttle