DTC 0401

DESCRIPTION
The intake air temperature sensor mounted to the air cleaner housing, detects intake air temperature and transmits a signal to the ECM.
The temperature sensing unit uses a thermistor which is sensitive to the change in temperature. Electrical resistance of the thermistor decreases in response to the temperature rise. This sensor is not used to control the engine system. It is used only for the on-board diagnosis.




DIAGNOSTIC TROUBLE CODE CONFIRMATION PROCEDURE
Procedure for malfunction A and B
WITH CONSULT
1) Wait until engine coolant temperature is less than 90°C (194°F).
(a) Turn ignition switch "ON".




(b) Select "DATA MONITOR" mode with CONSULT.
(c) Check the engine coolant temperature.
(d) If the engine coolant temperature is not less than 90°C (194°F), turn ignition switch "OFF" and cool down engine.
2) Turn ignition switch "ON".
3) Select "DATA MONITOR" mode with CONSULT.
4) Wait at least 5 seconds.

OR

WITH GST
1) Wait until engine coolant temperature is less than 90°C (194°F).
(a) Turn ignition switch "ON".
(b) Select MODE 1 with GST.
(c) Check the engine coolant temperature.




(d) If the engine coolant temperature is not less than 90°C (194°F), turn ignition switch "OFF" and cool down engine.
2) Turn ignition switch "ON" and wait at least 5 seconds.
3) Select MODE 3 with GST.

OR

WITH NO TOOLS
1) Wait until engine coolant temperature is less than 90°C (194°F).
(a) Turn ignition switch "ON".





(b) Check voltage between ECM terminal (51) and ground.

Voltage: More than 1.2 (V)

(c) If the voltage is not more than 1.2V, turn ignition switch "OFF" and cool down engine.
2) Turn ignition switch "ON" wait at least 5 seconds.
3) Turn ignition switch "OFF", wait at least 5 seconds and then turn "ON".
4) Perform "Diagnostic Test Mode II" (Self-diagnostic results) with ECM.




WIRING DIAGRAM




DIAGNOSTIC PROCEDURE

COMPONENT INSPECTION




Check resistance as shown in the figure.







If NG, replace intake air temperature sensor.