DTC Advanced Diagnostics: P0121 (K20C1) - Honda Civic FC/FK 2016-2021

DTC Advanced Diagnostics: P0121

DTC P0121:Throttle Position (TP) Sensor A Range/Performance Problem

General Description

The powertrain control module (PCM) monitors the throttle position (TP) sensor A circuit for physical range check. The diagnostic compares the voltages of the throttle position sensor A read at the closed and open positions of the throttle valve with their respective calibrated threshold values. If the TP sensor A output voltage is a specified value for a specified time, the PCM detects a malfunction and stores a DTC.

Monitor Execution, Sequence, Duration, DTC Type

Execution	Continuous
Sequence	None
Duration	0.14 second or more
DTC Type	Two drive cycles, MIL on

Enable Conditions

Condition
State of the engine	Running

Malfunction Threshold

Either of the conditions continues for at least 0.14 second.

	The TP sensor A output voltage [TP Sensor A] read at the closed position of the throttle valve is 0.2 V or more, or less than 0.42 V.
	The TP sensor A output voltage [TP Sensor A] read at the open position of the throttle valve is 4.8 V or less, or more than 4.38 V.

[ ]: 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.

	TP sensor A contact resistance changed
	Throttle body failure (TP sensor A)
	PCM internal circuit failure

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.