DTC P2121: App Sensor Circuits Out Of Correlation: Description

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The Accelerator Pedal Position (APP) sensor 1 is a potentiometer type sensor with the following 3 circuits:

A 5-volt reference circuit.
A low reference circuit.
A signal circuit.

The control module provides the APP sensor a 5-volt reference circuit and a low reference circuit. The APP sensor then provides the control module a signal voltage proportional to pedal movement. The APP sensor 1 signal voltage is low at rest and increases as the pedal is depressed. The APP sensor 2 signal voltage is also low at rest and increases as the pedal is depressed. When the control module detects that the APP sensor 1 signal and the APP sensor 2 signal circuits are out of correlation, this DTC sets.