SFI SYSTEM, Diagnostic DTC:P0112 and P0113

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

DESCRIPTION

A283580E01

The intake air temperature sensor is built into the manifold absolute pressure sensor, and monitors the intake air temperature. The intake air temperature sensor has a built-in 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 drops. The variations in resistance are reflected in the voltage applied to the ECM terminal (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 changes in the intake air temperature, 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.

Tip:

When the intake air temperature sensor output is outside the normal range, the ECM determines this to be a malfunction.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Memory

P0112

Intake Air Temperature Circuit Low Input

Intake air temperature sensor output voltage is 0.05 V or less for 0.5 seconds (3 trip detection logic).

  • Open or short in intake air temperature sensor circuit

  • Short to power source circuit

  • Intake air temperature sensor (manifold absolute pressure sensor)

  • ECM

Comes on

DTC stored

P0113

Intake Air Temperature Circuit High Input

Intake air temperature sensor output voltage is 4.95 V or more for 0.5 seconds (3 trip detection logic).

  • Short in intake air temperature sensor circuit

  • Intake air temperature sensor (manifold absolute pressure sensor)

  • ECM

Comes on

DTC stored
Tip:

When any of these DTCs are output, check the intake air temperature using the GTS. Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / Intake Air.

Intake Air Temperature

Malfunction

-40°C (-40°F)

Open circuit

140°C (284°F)

Short circuit

WIRING DIAGRAM

A415185E08

CONFIRMATION DRIVING PATTERN

DTC P0112 and P0113 are detected when the engine idles for approximately 5 minutes.

CAUTION / NOTICE / HINT

Note:

After replacing the ECM, perform idle learning.

Click here

Tip:

Read freeze frame data using the GTS. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.

PROCEDURE

  1. READ VALUE USING GTS (INTAKE AIR)

    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

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

      Powertrain > Engine and ECT > Data List

      Tester Display

      Intake Air

    5. Read the value displayed on the GTS.

      OK

      Same as actual intake air temperature.

      Result

      Result

      Proceed to

      -40°C (-40°F)

      A

      140°C (284°F)

      B

      Same as actual intake air temperature

      C
      Tip:

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

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

    B

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

    C

    CHECK FOR INTERMITTENT PROBLEMS

    Click here

    A

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

    1. Disconnect the manifold absolute pressure sensor connector.

      A429626C01

      *1

      Manifold Absolute Pressure Sensor

      *2

      ECM

      *a

      Front view of wire harness connector

      (to Manifold Absolute Pressure Sensor)

      -

      -

    2. Connect terminals 4 (THA) and 2 (E2) of the manifold absolute pressure sensor connector on the wire harness side.

    3. Connect the GTS to the DLC3.

    4. Turn the ignition switch to ON.

    5. Turn the GTS on.

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

      Powertrain > Engine and ECT > Data List

      Tester Display

      Intake Air

    7. Read the value displayed on the GTS.

      Standard Value

      140°C (284°F)

    Result

    Proceed to

    OK

    NG
    OK

    REPLACE INTAKE MANIFOLD

    Click here

    NG

  3. CHECK HARNESS AND CONNECTOR (MANIFOLD ABSOLUTE PRESSURE SENSOR - ECM)

    1. Disconnect the manifold absolute pressure sensor 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

      B7-4 (THA) - B31-128 (THA)

      Always

      Below 1 Ω

      B7-2 (E2) - B31-127 (E21)

      Always

      Below 1 Ω

    Result

    Proceed to

    OK

    NG
    OK

    REPLACE ECM

    Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

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

    1. A255925C89

      *1

      Manifold Absolute Pressure Sensor

      *2

      ECM

      Disconnect the manifold absolute pressure sensor connector.

    2. Connect the GTS to the DLC3.

    3. Turn the ignition switch to ON.

    4. Turn the GTS on.

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

      Powertrain > Engine and ECT > Data List

      Tester Display

      Intake Air

    6. Read the value displayed on the GTS.

      Standard Value

      -40°C (-40°F)

    Result

    Proceed to

    OK

    NG
    OK

    REPLACE INTAKE MANIFOLD

    Click here

    NG

  5. CHECK HARNESS AND CONNECTOR (MANIFOLD ABSOLUTE PRESSURE SENSOR - ECM)

    1. Disconnect the manifold absolute pressure sensor 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

      B7-4 (THA) or B31-128 (THA) - Body ground

      Always

      10 kΩ or higher

    Result

    Proceed to

    OK

    NG
    OK

    REPLACE ECM

    Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR