Code 0401

The intake air temperature sensor is 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 directly used to control the engine system. It is used only for the on-board diagnosis.




DIAGNOSTIC CHART




DIAGNOSTIC TROUBLE CODE CONFIRMATION PROCEDURE

Procedure for malfunctions A and B
CONSULT
1) Wait until engine coolant temperature is less than 90°C (194°F).
(1) Turn ignition switch "ON".




(2) Select "DATA MONITOR" mode with CONSULT.
(3) Check the engine coolant temperature.
(4) 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 for at least 5 seconds.

OR

GST




1) Wait until engine coolant temperature is less than 90°C (194°F).
(1) Turn ignition switch "ON".
(2) Select MODE 1 with GST.
(3) Check the engine coolant temperature.
(4) 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 for at least 5 seconds.
3) Select MODE 3 with GST.

OR

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




(2) Check voltage between ECM terminal (59) and ground.

Voltage: More than 1.2 (V)

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










COMPONENT INSPECTION
Intake air temperature sensor
Check resistance as shown in the figure.




WIRING DIAGRAM