LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Lexus >> 2012 >> IS 350 Base, AWD >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> Engine Control System (Diagnostic Codes (P0010-P014F)) >> SFI System >> DTC P0112: Intake Air Temperature Circuit Low Input; DTC P0113: Intake Air Temperature Circuit High Input >> Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

DTC P0112: Intake Air Temperature Circuit Low Input; DTC P0113: Intake Air Temperature Circuit High Input: Procedure

  1. READ VALUE USING INTAKE AIR TEMPERATURE SENSOR (INTAKE AIR) 
    1. Connect Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the tester on.
    4. Enter the following menus: Powertrain / Engine / 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
      Higher than 128°C (262°F) B
      Same as actual IAT C

      HINT: 

      • If there is an open circuit, Techstream indicates -40°C (-40°F).
      • If there is a short circuit, Techstream indicates higher than 128°C (262°F).

    B → See step   4 

    C → CHECK FOR INTERMITTENT PROBLEMS 

    A: Go to next step 

  2. CHECK INTAKE AIR TEMPERATURE SENSOR (CHECK FOR OPEN IN SENSOR) 
    1. Confirm good connection of Mass Air Flow (MAF) meter.
      Fig 1: E29 MAF Meter Connector
      GTY359447Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Disconnect the E29 MAF meter connector.
    3. Connect terminals THA and E2 of the MAF meter wire harness side connector.
    4. Connect Techstream to the DLC3.
    5. Turn the engine switch on (IG).
    6. Turn the tester on.
    7. Enter the following menus: Powertrain / Engine / Data List / Intake Air.
    8. Read the value displayed on the tester.

      Standard

      Higher than 128°C (262°F)

    9. Reconnect the MAF meter connector.

    OK → REPLACE MASS AIR FLOW METER 

    NG: Go to next step 

  3. CHECK ECM (CHECK FOR OPEN IN ECM) 
    1. Confirm good connection of the ECM.
      Fig 2: Identifying ECM Connector E5
      GTY145492Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Disconnect the E29 MAF meter connector.
    3. Connect terminals THA and ETHA of the E5 ECM connector.

      HINT: 

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

    4. Connect Techstream to the DLC3.
    5. Turn the engine switch on (IG).
    6. Turn the tester on.
    7. Enter the following menus: Powertrain / Engine / Data List / Intake Air.
    8. Read the value displayed on the tester.

      Standard

      Higher than 128°C (262°F)

    9. Reconnect the MAF meter connector.

    OK → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    NG → See step   6 

  4. CHECK INTAKE AIR TEMPERATURE SENSOR (CHECK FOR SHORT IN SENSOR) 
    1. Disconnect the E29 MAF meter connector.
      Fig 3: Identifying MAF Meter Connector
      GTY132985Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Connect Techstream to the DLC3.
    3. Turn the engine switch on (IG).
    4. Turn the tester on.
    5. Enter the following menus: Powertrain / Engine / 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: Go to next step 

  5. CHECK ECM (CHECK FOR SHORT IN ECM) 
    1. Disconnect the E5 ECM connector.
      Fig 4: Identifying E5 ECM Connector
      GTY133282Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Connect Techstream to the DLC3.
    3. Turn the engine switch on (IG).
    4. Turn the tester on.
    5. Enter the following menus: Powertrain / Engine / Data List / Intake Air.
    6. Read the value displayed on the tester.

      Standard

      -40°C (-40°F)

    7. Reconnect the ECM connector.

    OK → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    NG → See step   7 

  6. REPLACE ECM. Refer to  REMOVAL 
  7. REPLACE ECM. Refer to  REMOVAL