DTC Advanced Diagnostics: P0127 (K20C1) - Honda Civic FC/FK 2016-2021

DTC Advanced Diagnostics: P0127

DTC P0127:Intake Air Temperature (IAT) Sensor Too High

General Description

The powertrain control module (PCM) monitors intake air temperature (IAT) sensor 1 for rationality malfunctions. IAT sensor 1 is a thermistor that detects intake air temperature, which is utilized for air/fuel ratio feedback control to compensate for the atmospheric density fluctuations that accompany changes in intake air temperature. The IAT sensor 1 resistance varies depending on temperature. The sensor resistance and the output voltage increase as the intake air temperature decreases. The temperature value, linearized over sensor characteristic line, is continuously monitored against the threshold. If the IAT sensor 1 output temperature is a specified value, the PCM detects a malfunction and stores a DTC.

Monitor Execution, Sequence, Duration, DTC Type

Execution	Multiple
Sequence	None
Duration	0.5 second or more
DTC Type	Two drive cycles, MIL on

Enable Conditions

Condition	Minimum	Maximum
Vehicle speed [Vehicle Speed]	0 mph (0 km/h)	–
Intake air amount	0 kg/h (0 lbs/h)	1,020 kg/h (2,248 lbs/h)
State of the engine	Running

[ ]: HDS Parameter

Malfunction Threshold

The IAT sensor 1 output temperature is 247.93 °F (119.96 °C) - 256.93 °F (124.96 °C) or more for at least 10 seconds.

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.

	IAT sensor 1 TA2 line short to ground
	IAT sensor 1 failure
	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.