P0127

P0127 IAT Sensor

Component Description

The intake air temperature sensor is built into 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 temperature rise.

[Reference data]









*: This data is reference value and is measured between ECM terminal 34 (Intake air temperature sensor) and ground.

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 SDT

1) Wait until engine coolant temperature is less than 96 °C (205 °F)
a) Turn ignition switch ON.
b) Select "Data list" mode with SDT.
c) Check the engine coolant temperature.
d) If the engine coolant temperature is not less than 96 °C (205 °F), turn ignition switch OFF and cool down engine.
- Perform the following steps before engine coolant temperature is above 96 °C (205 °F).
2) Turn ignition switch ON.
3) Select "Data list" mode with SDT.
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 SDT" 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 Check] Power Supply and Ground Circuit Check.






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). Refer to [Air Cleaner and Air Duct: Exploded View] Exploded View.

3. CHECK INTERMITTENT INCIDENT

Refer to [Service Information for Electrical Incident: Intermittent Incident] Service Information for Electrical Incident: Intermittent Incident.


INSPECTION END

Component Inspection

Intake Air Temperature Sensor

1) Check resistance between intake air temperature sensor (1) terminals 5 and 6 under the following conditions.











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