Fix code P2138 Accelerator Pedal Position (APP) Sensor 1-2 Correlation
If your vehicle has set a P2138 Accelerator Pedal Position (APP) Sensor 1-2 Correlation trouble code, read this description to find out what it means.
Many accelerator pedal position sensors actually have two sensors inside. The computer sends a 5-volt reference signal to both sensors and sees the return ground as a sign that the reference signal is reaching the sensors and returning back to the computer. A third wire carries that actual position signal.
To test the APP, the vehicle must meet the following conditions:
System voltage must be greater than 5.23-volts
Ignition switch is in the ACC, RUN, or CRANk position
Trouble codes P0641, P0651, P2120, P2122, P2123, P2125, P2127, and P2128are NOT already stored in the computer
The computer looks at the difference between APP 1 and APP 2. If the two values exceed a predetermined value for more than .5-sec, it will set a P2138 code.
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©, 2013 Rick Muscoplat
Posted on by Rick Muscoplat