DTC P0127 (K20C1) (2017 2018 2019)
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 higher than the maximum expected intake air temperature 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 | 5 seconds 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 | |
Malfunction Threshold
The IAT sensor 1 output temperature is higher than the maximum expected intake air temperature for at least 5 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 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.