P0127

DTC P0127 IAT SENSOR





Component Description






The intake air temperature sensor is built-into mass air flow sensor.
The sensor 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.

[Reference data]











CAUTION:
Never use ECM ground terminals when measuring input/output voltage. Doing so may result in damage to the ECM's transistor.
Use a ground other than ECM terminals, such as the ground.




On Board Diagnosis Logic









DTC Confirmation Procedure

NOTE:
If DTC Confirmation Procedure has been previously conducted, always perform the following before conducting the next step.
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.

CAUTION:
Always drive vehicle at a safe speed.
TESTING CONDITION:
This test may be conducted with the drive wheels lifted in the shop or by driving the vehicle. If a road test is expected to be easier, it is unnecessary to lift the vehicle.

WITH CONSULT-III
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-III.
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.
- Perform the following steps before engine coolant temperature is above 90�C (194�F).
2. Turn ignition switch ON.
3. Select "DATA MONITOR" mode with CONSULT-III.
4. Start engine.
5. Hold vehicle speed at more than 70 km/h (43 MPH) for 100 consecutive seconds.
6. Check 1st trip DTC.
7. If 1st trip DTC is detected, go to "Diagnosis Procedure".

WITH GST
Follow the procedure "WITH CONSULT-III" above.




Diagnosis Procedure
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body. Refer to Power Supply And Ground Circuit.






OK or NG
OK - GO TO 2.
NG - Repair or replace ground connections.
2.CHECK INTAKE AIR TEMPERATURE SENSOR
Refer to "Component Inspection".
OK or NG
OK - GO TO 3.
NG - Replace mass air flow sensor (with intake air temperature sensor).
3.CHECK INTERMITTENT INCIDENT
Refer to Description Diagnosis Procedure.
Refer to EC-IATS.
- INSPECTION END




Component Inspection

INTAKE AIR TEMPERATURE SENSOR
1. Check resistance between mass air flow sensor terminals 1 and 2 under the following conditions.
















2. If NG, replace mass air flow sensor (with intake air temperature sensor).




Removal and Installation

MASS AIR FLOW SENSOR
Refer to Service and Repair.