P0113 Intake Air Temperature Sensor 1 Circuit High Input - Automotive Repair Guides & Equipment

COMPONENT LOCATION

GENERAL DESCRIPTION

The Intake Air Temperature Sensor (IATS) is installed into the Mass Air Flow Sensor (MAFS). 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.

DTC DESCRIPTION

Checking output signals of IATS every 20 sec. under detecting condition, if an output signal is over 4.9V for more than 10 sec., ECM sets P0113.

DTC DETECTING CONDITION

Item

Detecting Condition

Possible Cause

DTC Strategy

This code detects a continuous short to high in either the signal circuit or the sensor

1.	Connecting condition

2.	Open or short to battery in harness

3.	Open in ground harness

IATS

ECM

Enable Conditions

Engine running state

No Vehicle speed sensor fault

No ECTS fault

No MAFS fault

Intake airflow < 15 g/s

Vehicle speed < 25kph(9.3mph)

Engine coolant temperature > 50°C(122°F)

Threshold value

Intake air temperature sensor’s voltage > 4.9V

Diagnosis Time

Continuous (More than 10 seconds failure for every 20 seconds test)

MIL On Condition

3 Driving Cycles

SPECIFICATION

Temp. (°C)	Resistance (kΩ)	Temp. (°C)	Resistance (kΩ)
-40	40.93 ~ 48.35	20	2.31 ~ 2.57
-20	13.89 ~ 16.03	40	1.08 ~ 1.21
0	5.38 ~ 6.09	60	0.54 ~ 0.66
10	3.48 ~ 3.90	80	0.29 ~ 0.34

DIAGNOSTIC CIRCUIT DIAGRAM

SIGNAL WAVEFORM & DATA

Fig.1) Normal data of IATS & ECTS & EOTS at ig on

Fig.2) Normal data of IATS & ECTS & EOTS after warming up.

Fig.3) Normal waveform of IATS

The output signals of IATS & ECTS change smoothly without any rapid changes. These 2 sensor have almost the same characteristic signal during the early period after start. It means that the temperatures of intake air and engine coolant are depended on the temperature of atmosphere. Meanwhile, During engine warm up the output signal of the ECT will change quicker than the IAT signal. even it may not change almost.

MONITOR GDS DATA

1.	Connect GDS to Data Link Connector(DLC).

IG “ON”.

3.	Select “DTC” button, and then Press “DTC Status” to check DTC’s information from the DTCs menu.

4.	Read “DTC Status” parameter.

Is parameter displayed “Present fault”?

	▶ Go to “Terminal and Connector inspection” procedure.
	▶ Fault is intermittent caused by poor contact in the sensor’s and/or ECM’s connector or was repaired and ECM memory was not cleared. Thoroughly check connectors for looseness, poor connection, ending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary

TERMINAL AND CONNECTOR INSPECTION

1.	Many malfunctions in the electrical system are caused by poor harness and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.

2.	Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.

Has a problem been found?

	▶ Repair as necessary
	▶ Go to ” Signal Circuit Inspection ” procedure.

SIGNAL CIRCUIT INSPECTION

■ Check voltage

1.	IG “OFF” and disconnect IATS connector.

IG “ON”

Measure voltage between signal terminal of IATS harness connector and chassis ground.

Specification : Approx. 3.3V

Is the measured voltage within specification ?

	▶ Go to “Ground Circuit Inspection” procedure.
	▶ If the voltage is 0V, go to “Check open in harness” as follows. If the voltage is more than 5.1V, go to “Check short to battery in harness” as follows.

■ Check short to battery in harness

1.	IG “OFF” and disconnect IATS connector and ECM connector.

2.	Measure resistance between signal terminal of IATS harness connector and power terminal of Baro Sensor harness connector.

Measure resistance between signal terminal of IATS harness connector and signal terminal of Baro Sensor harness connector.

Specification : Infinite

Is the measured resistance within specification ?

	▶ Go to “Component Inspection” procedure.
	▶ Repair short to battery in harness .

■ Check open in harness

1.	IG “OFF” and disconnect IATS connector and ECM connector.

Measure resistance between signal terminal of IATS harness connector and IATS signal terminal of ECM harness connector.

Specification : below 1Ω

Is the measured resistance within specification ?

	▶ Go to “Ground Circuit Inspection” procedure.
	▶ Repair open in harness .

GROUND CIRCUIT INSPECTION

■ Check open in harness

1.	IG “OFF” and disconnect IATS connector and then IG “ON”.

2.	Measure voltage between signal terminal of IATS harness connector and chassis ground.(Measurement “A”)

Measure voltage between signal and ground terminals of IATS harness connector.(Measurement “B”)

Specification : Voltage difference between measurement “A” and “B” is below 200mV.

Is the measured voltage within specification ?

	▶ Go to “Component Inspection” procedure.
	▶ Repair contact resistance or open in harness

COMPONENT INSPECTION

■ Check IATS resistance

1.	IG “OFF” and disconnect IATS connector.

Measure resistance between signal and ground terminals of IATS connector after checking out the temperature of IATS with GDS (Component Side)

Specification :

Temp. (°C)	Resistance (kΩ)	Temp. (°C)	Resistance (kΩ)
-40	40.93 ~ 48.35	20	2.31 ~ 2.57
-20	13.89 ~ 16.03	40	1.08 ~ 1.21
0	5.38 ~ 6.09	60	0.54 ~ 0.66
10	3.48 ~ 3.90	80	0.29 ~ 0.34

Is the measured resistance within specification ?

▶ Substitute with a known – good ECM and check for proper operation. If the problem is corrected, replace ECM

There is a memory reset function on GDS that can erase optional parts automatically detected and memorized by ECM. Before or after testing ECM on the vehicle, use this function to reuse the ECM on the others

▶ Substitute with a known – good IATS and check for proper operation. If the problem is corrected, replace IATS

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