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

The intake air temperature sensor is located in the intercooler outlet.
1. Without unplugging the connector, slide back the protective boot from the intake air temperature sensor harness plug, and connect an ohmmeter between the terminals.
Resistance should be 400 - 700 ohms
2. If the resistance values are within specification, check the wiring between the sensor and the control unit.
3. Remove the control unit cover (located in the passenger side footwell), and disconnect the harness plug from the control unit.
4. Connect an ohmmeter between terminal 23 of the control unit harness plug, and terminal 1 (the lower wire) of the temp. sensor.
Resistance should be 0 ohms.
5. Connect the ohmmeter between terminal 23 of the control unit harness plug, and terminal 2 of the temp. sensor.
Resistance should be 400 - 700 ohms.
6. Connect the ohmmeter between terminal 24 of the control unit harness plug and terminal 1 of the temp. sensor.
Resistance should be 400 - 700 ohms.
7. Connect the ohmmeter between terminal 24 of the control unit harness plug and terminal 2 of the temp. sensor.
Resistance should be 0 ohms.
8. If the resistances are not within specification, cut the wires at the temperature sensor, and check the resistance between the terminals of the sensor.
Resistance should be 400 - 700 ohms.
9. If the resistance is not within specifications, replace the sensor.

Note: When installing a new air temperature sensor, the leads from the new sensor must be soldered to the harness wires. If crimp type connectors are used, over time, corrosion could cause erroneous resistance readings to be sent to the control unit.

10. If the sensor is OK, check for a short or open circuit in the wiring, and repair as necessary.
11. If the wiring is OK, replace the control unit and repeat the test.