Accelerator pedal position sensor

About APP Sensor

1. Accelerator Pedal Position sensor Video link : https://youtu.be/pjSLQJRZ7UA Presented by Sakthigurusamy.S

2. Introduction The APP sensor is fixed to the throttle body of the electronic throttle control system with intelligence ( ETCSi ). The functional principle to the AAP sensor involves conversion of the accelerator pedal movement into a voltage signal . The accelerator position information is transferred to the throttle actuator control (TAC) module and the powertrain control module (PCM ). The accelerator position sensor is made up of two individual sensors, with both sensors designed to have individual sensor return wiring and each have a varying voltage range.

3. Contd … The PCM system receives and processes the electrical signals from the ACC sensors along with signals from the direct current (DC) motor, which sets the throttle plate via a throttle cable . As the air travels through the throttle passage to the intake manifold, it activates airflow sensors that manipulates the engine control unit and forces fuel into the fluid injector system . The AAP sensor system is typically known as the ‘drive by wire’ system and, as mentioned, delivers information to the engine control module systems about the accelerator pedal position in addition to the information about the speed at which the driver is pushing on the gas pedal.

4. Working principle The application of alternating voltage to the transmission coil produces a magnetic field which induces voltages in the receiver coils. A current is also induced in the rotor conductive loops which, in turn, influences the magnetic field of the receiver coils. Voltage amplitudes are produced depending on the position of the rotor relative to the receiver coils in the stator. These are processed in an electronic evaluation unit and then transmitted to the control unit in the form of direct-current voltage.

5. APP sensor(Electronic Throttle) Generally called as drive by wire. Different names depending on the manufacturer. Drive by wire integrates an electronically controlled throttle plate with a computer. Safety features such as Deaccelerator if vehicle goes out of control.

6. features This sensor is importance to drive by wire system. ECM with accelerator pedal position as well as rate of change or how fast the driver is pushing the gas pedal ECM with cruise control,automatic idle adjustment and deaccelerator as safety.

7. App dual potentiometer PP sensor is potentiometer or variable resistor with second potentiometer acting as redundant sensor. PP has two or three position sensors,one is first sensor and other is main input. Two or more potentiometer to make redundancy. If discrepancy the ECM sets a code and goes into reduced performance.

8. Operation mode Reverse mode: ECM changes the accelerator pattern of the vehicle when backing up. If PP sensor fails,ECM cuts rejector pulsation every other revolution is the event of PP failure reduces performance

9. Limp in mode APP 1&2 discrepancy will set the system in Limp in mode. If reference voltage or ground is lost to one of the potentiometer, others are still able to perform the operation. The series of potentiometer within PP sensor are wired differently for redundancy. Understanding the wiring pattern is important for diagnosis .

10. Operation One APP signal goes up while others signal goes down. Engine control module in order to control the vehicles acceleration both modules communicate via serial data line as APP signal changes the ECM commands. Excessive throttle opening creates the GPS signal discrepancy trigerring the ECM into setting a code.

11. SYMPTOMS OF A FAULTY If the accelerator pedal sensor fails, the following fault symptoms may occur: Increased engine idling speed Vehicle does not respond if the accelerator pedal is pressed Vehicle switches to "limp-home mode" Engine warning light in the cockpit illuminates

12. CAUSE OF FAILURE A failure could have a number of different causes: Damaged cables or connections on the accelerator pedal sensor Missing voltage and ground supply Faulty electronic evaluation unit in the sensor

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