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

A132329E07

  • The intake air temperature sensor, mounted on the mass air flow meter, monitors the intake air temperature. The intake air temperature sensor has a built-in thermistor with a resistance that varies according to the temperature of the intake air. When the intake air temperature becomes low, the resistance of the thermistor increases. When the temperature becomes high, the resistance drops. These variations in resistance are transmitted to the ECM as voltage changes (see Fig. 1).

  • The intake air temperature sensor is powered by a 5 V supply from the THA terminal of the ECM, 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, the voltage at terminal THA varies accordingly. Based on this signal, the ECM increases the fuel injection volume when the engine is cold to improve driveability.

    Tip:

    When DTC P0112 or P0113 is stored, the ECM enters fail-safe mode. During fail-safe mode, the intake air temperature is estimated to be 20°C (68°F) by the ECM. Fail-safe mode continues until a pass condition is detected.

DTC No.

DTC Detection Condition

Trouble Area

P0112

A short in the 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

An open in the 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
Tip:

When either of these DTCs is output, check the intake air temperature by entering the following menus on the GTS: Powertrain / Engine and ECT / Data List / Intake Air.

Temperature Displayed

Malfunction

-40°C (-40°F)

Open circuit

140°C (284°F) or higher

Short circuit

WIRING DIAGRAM

A162760E84

CAUTION / NOTICE / HINT

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 TEMPERATURE)

    1. Connect the GTS to the DLC3.

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

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

    4. Read the value displayed on the GTS.

      Standard

      Same as actual intake air temperature.

      Table 1. Result

      Result

      Proceed to

      Temperature displayed is -40°C (-40°F)

      A

      Temperature displayed is 140°C (284°F) or higher

      B

      Temperature displayed 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) or higher.

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

    CHECK FOR INTERMITTENT PROBLEMS

    (Click here)

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

    1. U121754E02

      Confirm good connection at the mass air flow meter.

    2. Disconnect the mass air flow meter connector.

    3. Connect terminals 1 (THA) and 2 (E2) of the MAF meter wire harness side connector.

    4. Connect the GTS to the DLC3.

    5. Turn the ignition switch to ON and turn the GTS on.

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

    7. Read the value displayed on the GTS.

      Standard

      140°C (284°F) or higher.

      Tip:

      Perform "Inspection After Repair" after replacing the mass air flow meter (Click here).

      Table 2. Text in Illustration

      *1

      Mass Air Flow Meter

      *2

      ECM

      *a

      Front view of wire harness connector

      (to Mass Air Flow Meter)

    8. Reconnect the mass air flow meter connector.

    REPLACE MASS AIR FLOW METER

    (Click here)

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

    1. 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 (Check for Open)

      Tester Connection

      Condition

      Specified Condition

      C3-1 (THA) - C111-138 (THA)

      Always

      Below 1 Ω

      C3-2 (E2) - C111-139 (ETHA)

      Always

      Below 1 Ω

    4. Reconnect the mass air flow meter connector.

    5. Reconnect the ECM connector.

    REPLACE ECM

    (Click here)

    REPAIR OR REPLACE HARNESS OR CONNECTOR (MASS AIR FLOW METER - ECM)

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

    1. A211723E16

      Disconnect the mass air flow meter connector.

    2. Connect the GTS to the DLC3.

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

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

    5. Read the value displayed on the GTS.

      Standard

      -40°C (-40°F)

      Tip:

      Perform "Inspection After Repair" after replacing the mass air flow meter (Click here).

      Table 3. Text in Illustration

      *1

      Mass Air Flow Meter

      *2

      ECM

    6. Reconnect the mass air flow meter connector.

    REPLACE MASS AIR FLOW METER

    (Click here)

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

    1. 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 (Check for Short)

      Tester Connection

      Condition

      Specified Condition

      C3-1 (THA) or C111-138 (THA) - Body ground

      Always

      10 kΩ or higher

    4. Reconnect the mass air flow meter connector.

    5. Reconnect the ECM connector.

    REPLACE ECM

    (Click here)

    REPAIR OR REPLACE HARNESS OR CONNECTOR (MASS AIR FLOW METER - ECM)