ECD SYSTEM, Diagnostic DTC:P0112, P0113

DTC Code DTC Name
P0112 Intake Air Temperature Circuit Low Input
P0113 Intake Air Temperature Circuit High Input

DESCRIPTION

The intake air temperature sensor is built into the Mass Air Flow (MAF) meter and senses the intake air temperature.

A thermistor built into the sensor changes its resistance value according to the intake air temperature.

The lower the intake air temperature, the higher the thermistor resistance value. The higher the intake air temperature, the lower the thermistor resistance value (See Fig. 1).

The intake air temperature sensor is connected to the ECM.

The 5 V power source voltage in the ECM is applied to the intake air temperature sensor from terminal THA via resistor R.

Resistor R and the intake air temperature sensor are connected in series. When the resistance value of the intake air temperature sensor changes in accordance with the intake air temperature, the voltage at terminal THA also changes. Based on this signal, the ECM increases the fuel injection volume to improve driveability with a cold engine.

A004P3DE01
*1 (Fig. 1)
*2 Resistance kΩ
*3 Acceptable
*4 Temperature °C (°F)
P0112
DTC Detection Drive Pattern DTC Detection Condition Trouble Area
Ignition switch ON for 0.5 seconds

Short in the IAT sensor for 0.5 seconds.

(1 trip detection logic)


  • Short in IAT sensor circuit

  • IAT sensor (built into mass air flow meter)

  • ECM

P0113
DTC Detection Drive Pattern DTC Detection Condition Trouble Area
Ignition switch ON for 0.5 seconds

Open in the IAT sensor for 0.5 seconds.

(1 trip detection logic)


  • Open in IAT sensor circuit

  • IAT sensor (built into mass air flow meter)

  • ECM

Related Data List
DTC No. Data List
P0112 Intake Air
P0113

Tech Tips


  • If DTC P0112 and/or P0113 is stored, the following symptoms may appear:


    • Misfire

    • Combustion noise

    • Black smoke

    • White smoke

    • Lack of power

  • When DTC P0112 or P0113 is stored, check the intake air temperature by entering the following menus: Powertrain / Engine and ECT / Data List / Intake Air.

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

WIRING DIAGRAM

A004OMIE02
*a IAT Sensor (Built into MAF Meter)

CAUTION / NOTICE / HINT

Note

After replacing the ECM, the new ECM needs registration (See page ) and initialization Click here.

Tech Tips


  • If DTCs relating to different systems are stored and they share terminal E2 as their ground, check this ground circuit first.

  • Read freeze frame data using the intelligent tester. Freeze frame data records the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, and other data from the time the malfunction occurred.

PROCEDURE


  1. READ VALUE USING INTELLIGENT TESTER (INTAKE AIR TEMPERATURE)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON and turn the tester on.

    3. Enter the following menus: Powertrain / Engine and ECT / Data List / Intake Air.

    4. Read the value.

      OK
      Same as actual intake air temperature.
      Result
      Result Proceed to
      -40°C (-40°F) A
      140°C (284°F) or higher B
      OK (same as actual intake air temperature) C

      Tech Tips


      • If there is an open circuit, the tester indicates -40°C (-40°F).

      • If there is a short circuit, the tester indicates 140°C (284°F) or more.


    B
    C
    A
  2. READ VALUE USING INTELLIGENT TESTER (CHECK FOR OPEN IN WIRE HARNESS)


    1. A004NS4E01
      Text in Illustration
      *1 MAF Meter
      *2 ECM
      *a

      Front view of wire harness connector

      (to MAF Meter)

      Disconnect the mass air flow meter connector.

    2. Connect terminals 4 (THA) and 5 (E2) of the mass air flow meter wire harness side connector.

    3. Connect the intelligent tester to the DLC3.

    4. Turn the ignition switch to ON and turn the tester on.

    5. Enter the following menus: Powertrain / Engine and ECT / Data List / Intake Air.

    6. Read the value.

      OK
      140°C (284°F) or higher
    7. Reconnect the mass air flow meter connector.


    OK
    NG
  3. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)


    1. A004TATE01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to MAF Meter)

      *b

      Front view of wire harness connector

      (to ECM)

      Disconnect the mass air flow meter connector.

    2. Disconnect the ECM connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      B2-4 (THA) - B39-110 (THA) Always Below 1 Ω
      B2-5 (E2) - B39-87 (ETHA) Always Below 1 Ω
    4. Reconnect the mass air flow meter connector.

    5. Reconnect the ECM connector.


    OK
    NG
  4. READ VALUE USING INTELLIGENT TESTER (CHECK FOR SHORT IN WIRE HARNESS)


    1. A004S7RE02
      Text in Illustration
      *1 MAF Meter
      *2 ECM

      Disconnect the mass air flow meter connector.

    2. Connect the intelligent tester to the DLC3.

    3. Turn the ignition switch to ON and turn the tester on.

    4. Enter the following menus: Powertrain / Engine and ECT / Data List / Intake Air.

    5. Read the value.

      OK
      -40°C (-40°F)
    6. Reconnect the mass air flow meter connector.


    OK
    NG
  5. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)


    1. A004QLVE02
      Text in Illustration
      *a

      Front view of wire harness connector

      (to MAF Meter)

      *b

      Front view of wire harness connector

      (to ECM)

      Disconnect the mass air flow meter connector.

    2. Disconnect the ECM connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      B2-4 (THA) or B39-110 (THA) - Body ground Always 10 kΩ or higher
    4. Reconnect the mass air flow meter connector.

    5. Reconnect the ECM connector.


    NG
    OK
  6. REPLACE ECM


    1. Replace the ECM Click here.


    NEXT
  7. CONFIRM GOOD CONNECTION TO SENSOR. IF OK, REPLACE MASS AIR FLOW METER.


    1. Replace the mass air flow meter Click here.


    NEXT
  8. REPAIR OR REPLACE HARNESS OR CONNECTOR


    1. Repair or replace the harness or connector.


    NEXT
  9. CONFIRM GOOD CONNECTION TO ECM. IF OK, REPLACE ECM.


    1. Replace the ECM Click here.


    NEXT
  10. REPLACE MASS AIR FLOW METER


    1. Replace the mass air flow meter Click here.


    NEXT
  11. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED


    1. Connect the intelligent tester to the DLC3.

    2. Clear the DTCs Click here.

    3. Turn the ignition switch to ON for 1 second.

    4. Enter the following menus: Powertrain / Engine and ECT / DTC.

    5. Confirm that the DTC is not output again.


    NEXT