Air Temperature Sensor ( Ambient / Intake ): Testing and Inspection

INTAKE AIR TEMPERATURE (IAT) SENSOR
The intake air temperature sensor (IAT Sensor) located in Mass Air Flow (MAF) sensor, is a resistor-based sensor for detecting the intake air temperature. The intake air temperature information from the sensor helps the PCM provide the necessary fuel injection.

Circuit Diagram:

Harness Inspection Procedures (Part 1):

Harness Inspection Procedures (Part 2):

Troubleshooting Procedures:

TROUBLESHOOTING HINTS




1. If the engine stalls occasionally, start the engine and shake the MAF sensor harness. If the engine stalls, check for poor contact at the MAF sensor connector.
2. If the MAF sensor output voltage is other than 0 when the ignition switch is turned on (do not start the engine), check for a faulty MAF sensor or PCM.
3. If the engine can idle even if the MAF sensor output voltage is out of specification, check for the following conditions;
- Disturbed air flow in the MAF sensor, disconnected air duct, and clogged air cleaner filter.
- Poor combustion in the cylinder, faulty ignition plug, ignition coil, injector, and incorrect comparison.
4. Even if no AFS malfunction occurs, check the mounting direction of the AFS.

NOTE:
- When the vehicle is new [within initial operation of about 500 km (300 miles)], the mass air flow sensor air quantity will be about 10% higher.
- Use an accurate digital voltmeter.
- Before checking, warm up the engine until the engine coolant temperature reaches 80 to 90 °C (176 ° to 198 °F).