2.
Probe(+) : IAT sensor harness connector NO3.
Probe(-) : Chassis ground.
caution
If the output voltage moves in reverse direction while air temperature changes,the IAT sensor is normal.
The Intake Air Temperature Sensor (IATS) is installed into the Manifold Absolute Pressure sensor (MAP). The IATS uses a thermistor whose resistance changes with the temperature.The electrical resistance of the IATS decreases as the temperature increases, and increases as the temperature decreases. The 5 V power source in the ECM is supplied to the IATS via a resistor in the ECM. That is, the resistor in the ECM and the thermistor in the IATS are connected in series. When the resistance value of the thermistor in IATS changes according to the intake air temperature, the signal voltage also changes. Using this signal, the information of the intake air temperature, the ECM corrects basic fuel injection duration and ignition timing.
The ECM sets DTC P0113 if the ECM detects signal voltage higher than the possible range of a properly operating IATS.
Item | Detecting Condition | Possible cause |
Monitoring Strategy | ● Signal check, high | ● Short in signal line ● Bad IATS ● Bad ECM |
Threshold value | ● Intake air temperature : > 128.25℃(262.85℉) | |
Enable Conditions | ||
Diagnostic Time | ● 0.2 sec | |
MIL on condition | ● 2 driving cycle |
Service standard
0℃ (32℉) : 4.0~4.4 V
20℃(68℉) : 3.0~3.8 V
40℃(104℉) : 2.5~3.0 V
80℃(176℉) : 1.0~1.5 V
This inspection procedure is recommended when service data with scan tool in not enough.
Start engine and warm up to operating temperature.
Probe(+) : IAT sensor harness connector NO3.
Probe(-) : Chassis ground.
If the output voltage moves in reverse direction while air temperature changes,the IAT sensor is normal.
Service standard
0℃ (32℉) : 4.0~4.4 V
20℃(68℉) : 3.0~3.8 V
40℃(104℉) : 2.5~3.0 V
80℃(176℉) : 1.0~1.5 V
This figure shows the waveform at terminal 3 of IATS at idle rpm.
The lower the temperature is, the closer the output voltage of IAT goes to 5 V.In case,when engine is warmed up,the output is 5 V.
Possible cause : Open signal and ground line,or sensor’s inner circuit open
In case,when engine is cold,the output is below 0.5V
Possible cause : Short between signal and groun line Bad ECM
If the output voltage moves in reverse direction while air temperature changes,the IAT sensor is normal.
In case there is no symptom and wrong data but DTC is shown
The problem may be intermittent so slightly shake the connector and harness vertically and horizontally to check if there is any data changes
If the data changes normally, the problem was intermittent so erase DTC and verify the same DTC reoccure.
Go to "Terminal and Connector inspection" procedure.
In case there is symptom and wrong data with DTC
Check open,short or connector’s connection for IATS.
Check the deterioration of IATS performance.
Go to "Circuit Inspection" procedure.
This figure shows the waveform at terminal 3 of IATS at idle rpm.
The lower the temperature is, the closer the output voltage of IAT goes to 5 V.In case,when engine is warmed up,the output is 5 V.
Possible cause : Open signal and ground line,or sensor’s inner circuit open
In case,when engine is cold,the output is below 0.5V
Possible cause : Short between signal and groun line Bad ECM
