SFI SYSTEM (w/ Secondary Air Injection System), Diagnostic DTC:P0110, P0112, P0113

DTC Code DTC Name
P0110 Intake Air Temperature Circuit
P0112 Intake Air Temperature Circuit Low Input
P0113 Intake Air Temperature Circuit High Input

DESCRIPTION

The Intake Air Temperature (IAT) sensor, mounted on the Mass Air Flow (MAF) meter, monitors the IAT. The IAT sensor has a built in thermistor with a resistance that varies according to the temperature of the intake air. When the IAT is low, the resistance of the thermistor increases. When the temperature is high, the resistance drops. These variations in resistance are transmitted to the ECM as voltage changes (see Figure 1).

The IAT sensor is powered by a 5 V supply from the THA terminal of the ECM, via resistor R.

Resistor R and the IAT sensor are connected in series. When the resistance value of the IAT sensor changes, according to changes in the IAT, the voltage at terminal THA also varies. Based on this signal, the ECM increases the fuel injection volume when the engine is cold to improve drivability.

A01BI2VE06

Tech Tips

When any of DTCs P0110, P0112 and P0113 are set, the ECM enters fail-safe mode. During fail-safe mode, the IAT is estimated to be 20°C (68°F) by the ECM. Fail-safe mode continues until a pass condition is detected.

DTC No. Proceed To DTC Detection Conditions Trouble Areas
P0110 Step 1

Open or short in Intake Air Temperature (IAT) sensor circuit for 0.5 seconds

(1 trip detection logic)

  • Open or short in IAT sensor circuit

  • IAT sensor (built into MAF meter)

  • ECM
P0112 Step 4

Short in Intake Air Temperature (IAT) sensor circuit for 0.5 seconds

(1 trip detection logic)

  • Short in IAT sensor circuit

  • IAT sensor (built into MAF meter)

  • ECM
P0113 Step 2

Open in Intake Air Temperature (IAT) sensor circuit for 0.5 seconds

(1 trip detection logic)

  • Open in IAT sensor circuit

  • IAT sensor (built into MAF meter)

  • ECM

Tech Tips

When any of these DTCs are set, check the Intake Air Temperature (IAT) by selecting the following menu items on an intelligent tester: Powertrain / Engine and ECT / Data List / Intake Air.

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

MONITOR DESCRIPTION

The ECM monitors the sensor voltage and uses this value to calculate the IAT. When the sensor output voltage deviates from the normal operating range, the ECM interprets this as a malfunction in the IAT sensor and sets a DTC.

Example:

If the sensor voltage output is -40°C (-40°F) for 0.5 seconds or more, the ECM determines that there is an open in the IAT sensor circuit, and sets DTC P0113. Conversely, if the voltage output is more than 140°C (284°F) for 0.5 seconds or more, the ECM determines that there is a short in the sensor circuit, and sets DTC P0112.

If the malfunction is not repaired successfully, a DTC is set 0.5 seconds after the engine is next started.

WIRING DIAGRAM

A01BH1LE01

INSPECTION PROCEDURE

Tech Tips


  • If other DTCs relating 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 an intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air-fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.

PROCEDURE


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


    1. Connect an intelligent tester to the DLC3.

    2. Turn the ignition switch to the ON position.

    3. Turn the tester ON.

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

    5. Read the value 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 HARNESS) Click here

    C

    CHECK FOR INTERMITTENT PROBLEMS

    A

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


    1. Confirm good connection of the connector to the Mass Air Flow (MAF) meter.

    2. A01BBUPE01

      Disconnect the A3 Mass Air Flow (MAF) meter connector.

    3. Connect terminals THA and E2 of the MAF meter wire harness side connector.

    4. Connect the intelligent tester to the DLC3.

    5. Turn the ignition switch to the ON position.

    6. Turn the tester ON.

    7. Select the following menu items: Powertrain / Engine and ETC / Data List / Intake Air.

    8. Read the value displayed on the tester.

      Standard
      140°C (284°F) or higher

    9. Reconnect the MAF meter connector.


    OK

    REPLACE MASS AIR FLOW METER

    NG

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


    1. Confirm good connection of the connectors to the ECM.

    2. A01BAJPE01

      Disconnect the A3 MAF meter connector.

    3. Connect terminals THA and E2 of the ECM connectors.

      Tech Tips

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

    4. Connect the intelligent tester to the DLC3.

    5. Turn the ignition switch to the ON position.

    6. Turn the tester ON.

    7. Select the following menu items: Powertrain / Engine and ECT / Data List / Intake Air.

    8. Read the value displayed on the tester.

      Standard
      140°C (284°F) or higher

    9. Reconnect the MAF meter connector.


    NG

    REPLACE ECM

    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR

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


    1. A01BGFRE09

      Disconnect the A3 MAF meter connector.

    2. Connect the intelligent tester to the DLC3.

    3. Turn the ignition switch to the ON position.

    4. Turn the tester ON.

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

    6. Read the value displayed on the tester.

      Standard
      -40°C (-40°F)

    7. Reconnect the MAF meter connector.


    OK

    REPLACE MASS AIR FLOW METER

    NG

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


    1. A01BC76E01

      Disconnect the D1 and D3 ECM connectors.

    2. Connect the intelligent tester to the DLC3.

    3. Turn the ignition switch to the ON position.

    4. Turn the tester ON.

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

    6. Read the value displayed on the tester.

      Standard
      -40°C (-40°F)

    7. Reconnect the ECM connector.


    NG

    REPLACE ECM

    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR