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

System Schematic:

To test the Intake Air Temperature Sensor, located on the air flow sensor, in the air cleaner housing. Remove the air flow sensor (AFS) connector and proceed as follows.



COMPONENT TEST

Component Test:

1. Measure the resistance between terminals 2 and 4.
Terminals 2: Intake air temperature output
Terminals 4: Sensor ground
Standard Values
Ambient Sensor
Temperature(°F) Resistance(Ohm)
32.......................6.0
68.......................2.7
176.....................0.4

Sensor Test:

2. Measure the resistance while heating the sensor using a hair drier. You should observe a reduction in resistance (less Ohms) in response to an increase in temperature at the sensor.
3. If the value deviates from the standard value or the resistance remains unchanged, replace the air flow sensor assembly.



HARNESS TEST

1. Disconnect the air flow sensor connector and Turn on the ignition.
2. Using a voltmeter, measure the power supply voltage between the harness connector terminal 2 and ground.

Voltage: 4.8 - 5.2 Volts.

3. Check for continuity between the air flow sensor harness connector terminal 4 and ground.

Continuity: Should Exist


If any of the previous tests produce unsatisfactory results, the harness will need to be repaired or replaced. Once repairs have been completed, road test the vehicle to confirm that the repair has corrected the problem.
If the same problem reoccurs, it is possible that there is an intermittent failure of the component or the ECU. Check for looseness at all harness junctions and test for an intermittent failure.