Accelerator pedal position sensor
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Accelerator pedal position sensor
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The position sensor is used to convert the driver's torque request according to the accelerator pedal position to an instruction that can be understood and processed by the engine control module. The sensor is mounted directly on the accelerator pedal.
Inside the position sensor are two potentiometers that vary the voltage to the control module inputs depending on the angle of the position sensor axle. The position sensor comprises a resistor ring with collector shoes. The collector shoes are fitted to the axle of the position sensor and move across the resistor ring in relation to the movement of the axle.
The potentiometer is supplied with 5V from pins 7 and 26 on the control module to pins 2 and 1 on the sensor. It is grounded through pins 4 and 5 on the sensor to control module pins 31 and 11.
Control module sensor inputs on pins 27 and 8 are connected to pins 3 and 6 on the position sensor, where the voltage will vary according to the angle of the sensor axle.
In order to obtain reliable information from the position sensor, it is made up of two potentiometers. Both are supplied with 5V but the signal to the control module is always twice the size on P2 as it is on P1, 0-5V on the one and 0-2.5 on the other. This is to safeguard the function of the position sensor as well as its diagnosis. See illustration of the internal sensor connections.
When the position sensor angle is less than about 9°, the potentiometer will be in idle position and the voltage on the control module inputs will be less than 1.0V and 0.5V respectively.
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Diagnostic trouble code P0122 will be generated if pedal sensor 1 is shorted to ground.
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Diagnostic trouble code P0123 will be generated if pedal sensor 1 is shorted to B+.
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Diagnostic trouble code P0222 will be generated if pedal sensor 2 is shorted to ground.
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Diagnostic trouble code P0223 will be generated if pedal sensor 2 is shorted to B+.
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Diagnostic trouble code P1271 will be generated if there is a plausibility error between circuit 1 and circuit 2.
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System reaction to a fault
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The DTC will be present irrespective of which potentiometer is at fault. A fault on both pedal sensors 1 and 2 will give a fixed idling speed of around 1500 rpm.
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Fuel quantity max 30mm
3
/combustion. Change complete pedal position sensor.
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