ECD SYSTEM (w/ EGR Cooler Bypass Valve), 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 (IAT) sensor is built into the mass air flow (MAF) meter and senses the intake air temperature.

A01KI7CE03

A thermistor built in the sensor changes its resistance value according to the IAT.

The lower the IAT, the greater the thermistor resistance value. The higher the IAT, the lower the thermistor resistance value (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 resistor R.

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 potential at terminal THA also changes. Based on this signal, the ECM increases the fuel injection volume to improve driveability with a cold engine.

DTC No. DTC Detection Condition Trouble Area
P0112

Short in intake air temperature sensor circuit for 0.5 seconds

(1 trip detection logic)

  • Short in intake air temperature sensor circuit

  • Intake air temperature sensor (built into mass air flow meter)

  • ECM
P0113

Open in intake air temperature sensor circuit for 0.5 seconds

(1 trip detection logic)

  • Open in intake air temperature sensor circuit

  • Intake air temperature sensor (built into mass air flow meter)

  • ECM

Tech Tips

When DTC P0112 or P0113 is detected, check the intake air temperature by entering the following menus on the intelligent tester: 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

A01KF2XE03

INSPECTION PROCEDURE

Tech Tips


  • If DTCs related to different systems that have terminal E2 as the ground terminal are output simultaneously, terminal E2 may have an open circuit.

  • 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.

Note

After replacing the ECM, the new ECM needs registration Click here and initialization Click here.

PROCEDURE


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


    1. Connect an intelligent tester to the DLC3.

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

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

    4. Read values displayed on the tester.

      Standard
      Same as actual Intake Air Temperature (IAT)
      Result
      Temperature Displayed Proceed To
      -40°C (-40°F) A
      140°C (284°F) or higher B
      Same as actual IAT C

      Tech Tips


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

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


    B

    READ VALUE USING INTELLIGENT TESTER (CHECK FOR SHORT IN WIRE HARNESS) Click here

    C

    CHECK FOR INTERMITTENT PROBLEMS Click here

    A

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


    1. A01KHN4E02
      Text in Illustration
      *1 MAF Meter
      *2 ECM
      *3 MAF Meter Connector
      *a Wire Harness Side
      *b Front View

      Disconnect the A25 MAF meter connector.

    2. Connect terminals THA and E2 of the MAF 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. Select the following menus: Powertrain / Engine and ECT / Data List / Intake Air.

    6. Read values displayed on the tester.

      Standard
      140°C (284°F) or higher

    7. Reconnect the MAF meter connector.


    OK

    CONFIRM GOOD CONNECTION TO SENSOR. IF OK, REPLACE MASS AIR FLOW METER Click here

    NG

  3. READ VALUE USING INTELLIGENT TESTER (CHECK FOR OPEN IN ECM)


    1. A01KF1RE03
      Text in Illustration
      *1 MAF Meter
      *2 ECM
      *3 ECM Connector

      Disconnect the A25 MAF meter connector.

    2. Connect terminals E12 and E13 of the ECM connectors.

      Tech Tips

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

    3. Connect the intelligent tester to the DLC3.

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

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

    6. Read values displayed on the tester.

      Standard
      140°C (284°F) or higher

    7. Reconnect the MAF meter connector.


    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    NG

    CONFIRM GOOD CONNECTION TO ECM. IF OK, REPLACE ECM Click here

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


    1. A01KFYJE71
      Text in Illustration
      *1 MAF Meter
      *2 ECM

      Disconnect the A25 MAF meter connector.

    2. Connect an intelligent tester to the DLC3.

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

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

    5. Read values displayed on the tester.

      Standard
      -40°C (-40°F)

    6. Reconnect the MAF meter connector.


    OK

    REPLACE MASS AIR FLOW METER Click here

    NG

  5. READ VALUE USING INTELLIGENT TESTER (CHECK FOR SHORT IN ECM)


    1. A01KI6KE03
      Text in Illustration
      *1 MAF Meter
      *2 ECM
      *3 ECM Connector

      Disconnect the A25 MAF meter connector.

    2. Disconnect the E12 and E13 ECM connectors.

    3. Connect an intelligent tester to the DLC3.

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

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

    6. Read values displayed on the tester.

      Standard
      -40°C (-40°F)

    7. Reconnect the MAF meter connector.

    8. Reconnect the ECM connectors.


    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    NG

    REPLACE ECM Click here