Test NTC-11: Checking Intake Air Temperature (IAT) Sensor
NOTE:
When performing this test, DO NOT allow more than 5 minutes between measuring temperature of IAT sensor with scan tool and measuring air temperature on inside of intake manifold with temperature probe.
- Turn ignition on with engine off. Using scan tool in SENSORS mode, read INTAKE AIR TMP DEG. This is the intake air temperature value for IAT sensor. Record this reading. Turn ignition off.
- Disconnect IAT sensor connector. On 4.7L, IAT sensor is located on intake manifold, near throttle body. See Fig 1 . On 5.2L and 5.9L, IAT sensor is located on intake manifold. See Fig 2 . On all models, remove IAT sensor.
- Using temperature probe, quickly measure air temperature on inside of intake manifold, where IAT sensor is mounted. If temperature of IAT sensor on scan tool is within 10 degrees of temperature obtained on temperature probe, reinstall IAT sensor. Go to next step. If temperature of IAT sensor on scan tool is not within 10 degrees of temperature obtained on temperature probe, check wiring between IAT sensor and Powertrain Control Module (PCM) for high resistance. PCM is located at passenger's side front corner of engine compartment on inner fender panel. If high resistance exists, repair wiring as necessary. Perform TEST VER-5 . If wiring is okay, replace IAT sensor. Perform TEST VER-5 .
- Inspect wiring harness and connectors between IAT sensor and Powertrain Control Module (PCM). PCM is located at passenger's side front corner of engine compartment on inner fender panel. Inspect IAT sensor connector and PCM connectors for corroded, pushed out, miswired or damaged terminals. Also, check for related Technical Service Bulletins (TSBs). If no problems and no related TSBs exist, go to next step. If any problems exist, repair wiring or connectors as necessary. Perform TEST VER-5 .
- Start engine and allow engine to idle. Wiggle wiring harness and connectors between PCM and IAT sensor while noting GOOD TRIP counter. If GOOD TRIP counter does not change to zero, test is complete. If GOOD TRIP counter changes to zero while wiggling wiring harness and connectors, repair wiring or connectors as necessary. Perform TEST VER-5 .