P0127

P0127 IAT SENSOR





Description





The intake air temperature sensor is built-into the mass air flow sensor (1). 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 rise in temperature.

NOTE:
ECM uses only the intake air temperature sensor (bank 1) for engine control and self-diagnosis. It does not use the intake air temperature sensor (bank 2).














DTC Logic

DTC DETECTION LOGIC

DTC Detection Logic:

DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
If DTC Confirmation Procedure has been previously conducted, always perform the following procedure before conducting the next test.
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.
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.
- GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE
With CONSULT-III
1. Wait until engine coolant temperature is less than 96�C (205�F)
- Turn ignition switch ON.
- Select "DATA MONITOR" mode with CONSULT-III.
- Check the engine coolant temperature.
If the engine coolant temperature is not less than 96�C (205�F), turn ignition switch OFF and cool down engine.

NOTE:
Perform the following steps before engine coolant temperature is above 96�C (205�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.

CAUTION:
Always drive vehicle at a safe speed.
6. Check 1st trip DTC.
With GST
Follow the procedure "With CONSULT-III" above.
Is 1st trip DTC detected?
YES - Go to P0127.
NO - INSPECTION END




Diagnosis Procedure
1.CHECK GROUND CONNECTION
1. Turn ignition switch OFF.
2. Check ground connection M95. Refer to Ground Inspection in Circuit Inspection.
Is the inspection result normal?
YES - GO TO 2.
NO - Repair or replace ground connection.
2.CHECK INTAKE AIR TEMPERATURE SENSOR
Refer to P0127.
Is the inspection result normal?
YES - GO TO 3.
NO - Replace mass air flow sensor (bank 1) (with intake air temperature sensor).
3.CHECK INTERMITTENT INCIDENT
Refer to Intermittent Incident.
- INSPECTION END




Component Inspection
1.CHECK INTAKE AIR TEMPERATURE SENSOR
1. Turn ignition switch OFF.
2. Disconnect mass air flow sensor (bank 1) harness connector.
3. Check resistance between mass air flow sensor (bank 1) terminals as follows.





Is the inspection result normal?
YES - INSPECTION END
NO - Replace mass air flow sensor (with intake air temperature sensor) (bank 1).