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DTC P2121

DTC P2121:  Accelerator Pedal Position (APP) Sensor A (Throttle Position (TP) Sensor D) Out of Range

General Description 

GHH306887Courtesy of HONDA, U.S.A., INC.

Accelerator pedal position (APP) sensor A is a part of the electronic throttle control system. It is used to convert the position of the accelerator pedal into electrical signals. Based on these signals, the powertrain control module (PCM) controls the throttle actuator so that the throttle position agrees with the accelerator pedal position. If the signal voltage from APP sensor A is a set value, the PCM detects a malfunction and stores a DTC.

Monitor Execution, Sequence, Duration, DTC Type 

Execution Continuous
Sequence None
Duration 6 seconds or more
DTC Type Two drive cycles, MIL on

Enable Conditions 

Condition  
Vehicle ON mode

Malfunction Threshold 

The APP sensor A output voltage [APP SENSOR A] is 0.69 V or less, or 4.99 V or more for at least 6 seconds.

[ ]: HDS Parameter

Possible Cause 

NOTE:  The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.

Diagnosis Details 

Conditions for setting the DTC 

When a malfunction is detected during the first drive cycle, a Pending DTC is stored in the PCM memory. If the malfunction returns in the next (second) drive cycle, the MIL comes on and a Confirmed DTC and the freeze data are stored.

Conditions for clearing the DTC 

The MIL is cleared if the malfunction does not return in three consecutive trips in which the diagnostic runs. The MIL, the Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command or by disconnecting the 12 volt battery.