DTC Advanced Diagnostics: P011B
DTC P011B:Intake Air Temperature (IAT) Sensor 1 Circuit Range/Performance

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 monitored at cold start against the positive deviation to the average value of all temperature sensors. If the difference between the IAT sensor 1 output temperature and mean value of all temperature sensors at cold start is more than a specified value for a specified time, the PCM detects a malfunction and stores a DTC.

Monitor Execution, Sequence, Duration, DTC Type
Execution
Once per driving cycle
Sequence
None
Duration
0.5 second or more
DTC Type
Two drive cycles, MIL on

Enable Conditions
Condition
Minimum
Maximum
Engine off time
6 hours
–
Vehicle
ON mode

Malfunction Threshold
The difference between the IAT sensor 1 output temperature and mean value of all temperature sensors at cold start is more than 44 °F (24 °C) for at least 0.5 second.

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 power
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.