DTC    P0110/24    Intake Air Temperature Circuit

DTC    P0112/24    Intake Air Temperature Circuit Low Input

DTC    P0113/24    Intake Air Temperature Circuit High Input

for Preparation Click here


DESCRIPTION

The Intake Air Temperature (IAT) sensor, built into the Mass Air Flow (MAF) meter, monitors the IAT. The IAT senor has a thermistor that varies its resistance depending on the temperature of the intake air. When the air temperature is low, the resistance in the thermistor increases. When the air temperature is high, the resistance decreases. The variations in resistance are communicated to the ECM as change in voltage (see Fig. 1). The IAT sensor is connected to the ECM. The 5 V power source voltage in the ECM is applied to the IAT sensor from terminal THA via resister R.
The resister R and the IAT sensor are connected in series. When the resistance value of the IAT sensor changes in accordance with changes in the IAT, the voltage at terminal THA also changes. Based on this signal, the ECM increases the fuel injection volume to improve the driveability during cold engine operation.
G036559E03
The Intake Air Temperature (IAT) sensor, mounted on the air cleaner hose, monitors the IAT.
The IAT sensor has a thermistor that varies its resistance depending on the temperature of the intake air. When the air temperature is low, the resistance in the thermistor increases. When the temperature is high, the resistance decreases. The variations in resistance are communicated to the ECM as changes in voltage (see Fig. 1).
The IAT sensor is connected to the ECM (see below). The 5 V power source voltage in the ECM is applied to the IAT sensor from terminal THA via resistor R.
The resistor R and the IAT sensor are connected in series. When the resistance value of the IAT sensor changes in accordance with changes in the IAT, the voltage at terminal THA also changes. Based on this signal, the ECM increases the fuel injection volume to improve the driveability during cold engine operation.

DTC No.
DTC Detection Condition
Trouble Area
P0110/24
Open or short in IAT sensor circuit for 0.5 seconds (1 trip detection logic)
  1. Open or short in IAT sensor circuit
  2. IAT sensor (built into MAF meter)
  3. ECM
P0112/24
Short in IAT sensor circuit for 0.5 seconds (1 trip detection logic)
  1. Open or short in IAT sensor circuit
  2. IAT sensor (built into MAF meter)
  3. ECM
P0113/24
Open in IAT sensor circuit for 0.5 seconds (1 trip detection logic)
  1. Open or short in IAT sensor circuit
  2. IAT sensor (built into MAF meter)
  3. ECM

HINT:
When DTC P0110/24, P0112/24 or P0113/24 is detected, check the intake air temperature by entering the following menus on the intelligent tester: Powertrain / Engine / Data List / Intake Air.

Temperature Displayed
Malfunction
-40°C (-40°F)
Open circuit
140°C (284°F) or more
Short circuit


WIRING DIAGRAM


A099771E02


INSPECTION PROCEDURE

HINT:
  1. If DTCs related to different systems that have terminal E2 as the ground terminal are output simultaneously, terminal E2 may have an open circuit.
  2. Read freeze frame data using the intelligent tester. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, if the engine was warmed up or not, and other data from the time the malfunction occurred.

NOTICE:
If the ECM is replaced, the new ECM needs initialization (Click here).


When using intelligent tester:

1.READ DATA LIST (INTAKE AIR TEMPERATURE)

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch ON and turn the intelligent tester ON.

  1. Enter the following menus: Powertrain / Engine / Data List / Intake Air.

  1. Read the values.

    OK:
    Same value as the actual air temperature.

    Result:
    Temperature Displayed
    		Proceed to
    -40°C (-40°F)
    		A
    140°C (284°F) or more
    		B
    OK (same as air temperature near to intake manifold)
    		C

    HINT:
    1. If there is an open circuit, the intelligent tester indicates -40°C (-40°F).
    2. If there is a short circuit, the intelligent tester indicates 140°C (284°F) or more.



B
Go to step 4

C
CHECK FOR INTERMITTENT PROBLEMS
A


2.READ DATA LIST (CHECK FOR OPEN IN WIRE HARNESS)
A114039E01

  1. Disconnect the A4 MAF meter connector.

  1. Connect terminals 4 and 5 of the MAF meter wire harness side connector.

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch ON and turn the intelligent tester ON.

  1. Enter the following menus: Powertrain / Engine / Data List / Intake Air.

  1. Read the values.

    OK:
    140°C (284°F) or more



OK
CONFIRM GOOD CONNECTION AT SENSOR. IF OK, REPLACE INTAKE AIR TEMPERATURE SENSOR
NG


3.READ DATA LIST (CHECK FOR OPEN IN ECM)
A099842E05

  1. Disconnect the A4 MAF meter connector.

  1. Connect terminals THA and E2 of the E8 ECM connector.

    HINT:
    Before checking, perform a visual and contact pressure check on the ECM connector.

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch ON and turn the intelligent tester ON.

  1. Enter the following menus: Powertrain / Engine / Data List / Intake Air.

  1. Read the values.

    OK:
    140°C (284°F) or more



OK
REPAIR OR REPLACE HARNESS AND CONNECTOR
NG

CONFIRM GOOD CONNECTION AT ECM. IF OK, REPLACE ECM 

4.READ DATA LIST (CHECK FOR SHORT IN WIRE HARNESS)
A083863E04

  1. Disconnect the A4 MAF meter.

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch ON and turn the intelligent tester ON.

  1. Enter the following menus: Powertrain / Engine / Data List / Intake Air.

  1. Read the values.

    OK:
    -40°C (-40°F)



OK
REPLACE INTAKE AIR TEMPERATURE SENSOR
NG


5.READ DATA LIST (CHECK FOR SHORT IN ECM)
A099843E03

  1. Disconnect the A4 MAF meter.

  1. Disconnect the E8 ECM connector.

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch ON and turn the intelligent tester ON.

  1. Enter the following menus: Powertrain / Engine / Data List / Intake Air.

  1. Read the values.

    OK:
    -40°C (-40°F)



OK
REPAIR OR REPLACE HARNESS AND CONNECTOR
NG

REPLACE ECM 


When not using intelligent tester:

1.CHECK ECM (THA VOLTAGE)
A066060E33

  1. Start the engine.

  1. Measure the voltage of the ECM connector.

    Standard voltage:
    Tester Connection
    		Condition
    		Specified Condition
    E8-31 (THA) -
    E8-28 (E2)
    		Idling, IAT at 20°C (68°F)
    		0.5 to 3.4 V



OK
CHECK FOR INTERMITTENT PROBLEMS
NG


2.INSPECT INTAKE AIR TEMPERATURE SENSOR
A114041E01

  1. Remove the MAF meter.

  1. Measure the resistance of the sensor.

    Standard resistance:
    Tester Connection
    		Condition
    		Specified Condition
    4 - 5
    		-20°C (-4°F)
    		13.6 to 18.4 kΩ
    4 - 5
    		20°C (68°F)
    		2.21 to 2.69 kΩ
    4 - 5
    		60°C (140°F)
    		0.49 to 0.67 kΩ



NG
REPLACE INTAKE AIR TEMPERATURE SENSOR
OK


3.CHECK WIRE HARNESS (ECM- INTAKE AIR TEMPERATURE SENSOR)
A114040E01

  1. Disconnect the E8 ECM connector.

  1. Disconnect the A4 MAF meter connector.

  1. Measure the resistance of the wire harness side connectors.

    Standard resistance:
    Tester Connection
    		Specified Condition
    E8-31 (THA) - A4-4 (THA)
    		Below 1 Ω
    E8-28 (E2) - A4-5 (E2)
    		Below 1 Ω
    E8-31 (THA) or A4-4 (THA) - Body ground
    		10 kΩ higher
    E8-28 (E2) or A4-5 (E2) - Body ground
    		10 kΩ higher



NG
REPAIR OR REPLACE HARNESS AND CONNECTOR
OK

REPLACE ECM