DTC P0111-Intake Air Temperature Sensor Rationality: Notes
For a complete wiring diagram, refer to appropriate SYSTEM WIRING DIAGRAMS article.
Theory of Operation
Intake Air Temperature Sensor performance looks at the outputs of three temperature sensors and compares them under cold start conditions. Following a start to run delay time, the outputs of the ambient, engine coolant, and intake air temperature sensors will be compared. If the engine coolant and ambient air temperature sensors agree and the intake air temperature does not agree, the intake air temperature sensor is declared as irrational.
- When Monitored:
The engine off time is greater than 480 minutes. Ambient Temperature if greater than 4 deg C (38 deg F).
- Set Condition:
After a calibrated amount of cool down time the PCM compares the ECT Sensor, IAT Sensor, and the Ambient Air Temp Sensor values. If the IAT Sensor value is not within 10 deg C of the other two temperature sensors. Two Trip Fault. Three good trips to turn off the MIL.
| Possible Causes |
|---|
| (K21) IAT SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE |
| (K21) IAT SIGNAL CIRCUIT OPEN |
| (K900) SENSOR GROUND CIRCUIT OPEN |
| (K21) IAT SIGNAL CIRCUIT SHORTED TO GROUND |
| (K21) IAT SIGNAL CIRCUIT SHORTED TO THE |
| (K900) SENSOR GROUND CIRCUIT |
| INTAKE AIR TEMPERATURE SENSOR |
| PCM |
Always perform the PRE-DIAGNOSTIC TROUBLESHOOTING PROCEDURE before proceeding.