DTC P2121: App Sensor Circuits Out Of Correlation: Description
WARNING: This page is about a different car, the 2003 GMC Envoy XL and 2003 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
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.