P0127
DTC 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.
CAUTION: Do not 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
CAUTION: Always drive vehicle at a safe speed.
NOTE: If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at least 10 seconds before conducting the next test.
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 "Diagnostic Procedure" below.
WITH GST
Follow the procedure "With CONSULT-III".
Step 1-2:
Step 3:
Diagnostic Procedure
Component Inspection
INTAKE AIR TEMPERATURE SENSOR
1. Check resistance between intake air temperature sensor (1) terminals 5 and 6 under the given conditions.
2. If NG, replace mass air flow sensor (with intake air temperature sensor).