DTC Advanced Diagnostics: P0111
DTC P0111: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. A stuck check of IAT sensor 1 is performed by checking if the intake air temperature read by the sensor has a sufficient dynamic range. The number of operating phases with high intake air temperatures (high phase) and low intake air temperatures (low phase) are counted as from engine start. The difference between the maximum and minimum intake air temperatures recorded since engine start is determined if a sufficient number of high and low phases occurred. If the difference is below the threshold value, the PCM detects a malfunction and stores a DTC.

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

Enable Conditions
To ensure a change of the intake air temperature, the engine must run in the following two operating ranges for at least 8 seconds for 5 times each
Condition
Minimum
Maximum
Engine coolant temperature [ECT Sensor 1]
121.93 °F (49.96 °C)
–
Vehicle speed [Vehicle Speed]
–
12 mph (20 km/h)
Intake air amount
–
52 kg/h (114 lbs/h)
Total intake air amount
0 kg (0 lbs)
–

Condition
Minimum
Maximum
Vehicle speed [Vehicle Speed]
31 mph (50 km/h)
–
Intake air amount
0 kg/h (0 lbs/h)
120 kg/h (264 lbs/h)
[ ]: HDS Parameter

Malfunction Threshold
The difference between stored maximum and stored minimum IAT sensor 1 temperature since the engine start is less than 0.82 °F (0.46 °C).

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 stuck
PCM internal circuit failure

Confirmation Procedure
Operating Condition
1.
Start the engine.
2.
Drive the vehicle at vehicle speed [Vehicle Speed] less than 12 mph (20 km/h) for a few minutes.
3.
Maintain the vehicle speed [Vehicle Speed] above 31 mph (50 km/h) for a few minutes.
Drive the vehicle in this manner only if the traffic regulations and ambient conditions allow.

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.