Intake Air Temperature Sensor Testing

INTAKE AIR TEMPERATURE SENSOR













OPERATION
- The intake air temperature sensor converts the engine intake air temperature into a voltage and inputs it to the engine control module, which then corrects the fuel injection rate, etc. based on the input signal.
- The 5 V power in the engine control module is supplied via a resistor in the module to the intake air temperature sensor. Via the sensor which is a kind of resistor, it is grounded in the engine control module. The intake air temperature sensor resistor has the characteristic of decreasing its resistance decreases as the intake air temperature rises.
- The intake air temperature sensor terminal voltage increases or decreases as the sensor resistance increases or decreases. Therefore, the intake air temperature sensor terminal voltage changes with the intake air temperature, decreasing as the temperature rises.

TROUBLESHOOTING HINTS
The intake air temperature sensor senses the intake air temperature in the air cleaner so that it may indicate a temperature different from outside temperature depending on engine operating state.




INSPECTION
Using Scan Tool

HARNESS INSPECTION




Check for continuity of the ground circuit.
- Connector: Disconnected
OK: GO TO STEP 2
NG: Repair the harness. (A5-49)




Measure the power supply voltage.
- Connector: Disconnected
- Ignition switch: ON
Voltage (V): 4.5 - 4.9
OK: STOP
NG: Repair the harness. (A6-62)

INTAKE AIR TEMPERATURE SENSOR CHECK
1. Disconnect the volume air flow sensor connectors.







2. Measure resistance between terminals (5) and (6).







3. Measure resistance while heating the sensor using a hair drier.
4. If resistance does not decrease as heat increases or the resistance remains unchanged, replace the volume air flow sensor assembly.