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Home >> Lexus >> 2012 >> IS 250 Base, RWD, Standard >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> Engine Control System (Diagnostic Codes (P0010-P0175)) >> SFI System >> DTC P0102: Mass or Volume Air Flow Circuit Low Input; DTC P0103: Mass or Volume Air Flow Circuit High Input >> Procedure
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DTC P0102: Mass or Volume Air Flow Circuit Low Input; DTC P0103: Mass or Volume Air Flow Circuit High Input: Procedure

  1. READ DTC OUTPUT (DTC P0102 OR P0103) 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG) (do not run the engine).
    3. Turn the Techstream on.
    4. Enter the following menus: Powertrain / Engine / Trouble Codes.
    5. Read the DTCs.

      Result

      Result Proceed to
      DTC P0102 is output A
      DTC P0103 is output B

    B → See step   6 

    A: Go to next step 

  2. INSPECT MASS AIR FLOW METER (POWER SOURCE VOLTAGE) 
    1. Disconnect the E29 Mass Air Flow (MAF) meter connector.
      Fig 1: E29 Mass Air Flow (MAF) Meter Connector
      GTY354147Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Turn the engine switch on (IG).
    3. Measure the voltage according to the value(s) in the table below.

      Standard voltage

      Tester Connection Specified Condition
      E29-3 (+B) - Body ground 11 to 14 V
    4. Reconnect the MAF meter connector.

    NG → See step   5 

    OK: Go to next step 

  3. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM) 
    1. Disconnect the E29 MAF meter connector.
    2. Disconnect the E5 ECM connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard resistance (Check for open)

      Tester Connection Specified Condition
      E29-5 (VG) - E5-27 (VG) Below 1 Ω
      E29-4 (E2G) - E5-26 (E2G) Below 1 Ω

      Standard resistance (Check for short)

      Tester Connection Specified Condition
      E29-5 (VG) or E5-27 (VG) - Body ground 10 kΩ or higher
    4. Reconnect the MAF meter connector.
    5. Reconnect the ECM connector.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  4. INSPECT MASS AIR FLOW METER 
    1. Perform On-vehicle Inspection. Refer to ON-VEHICLE INSPECTION .
    2. Inspect the function of the mass air flow meter.
      1. Connect the Techstream to the DLC3.
      2. Turn the engine switch on (IG).
      3. Turn the Techstream on.
      4. Start the engine.
      5. Enter the following menus: Powertrain / Engine / Data List / All Data / MAF.
      6. Check that the reading of the MAF value changes when the engine is raced.

        OK

        The reading changes.

    NG → See step   8 

    OK → See step   10 

  5. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - INTEGRATION RELAY) 
    1. Disconnect the E29 MAF meter connector.
    2. Remove the integration relay from the engine room R/B No. 2.
    3. Measure the resistance according to the value(s) in the table below.

      Standard resistance (Check for open)

      Tester Connection Specified Condition
      E29-3 (+B) - 2A-8 Below 1 Ω

      Standard resistance (Check for short)

      Tester Connection Specified Condition
      E29-3 (+B) or 2A-8 - Body ground 10 kΩ or higher
    4. Reconnect the MAF meter connector.
    5. Reinstall the integration relay.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK → See step   9 

  6. CHECK HARNESS AND CONNECTOR (SENSOR GROUND) 
    1. Measure the resistance according to the value(s) in the table below.

      Standard resistance

      Tester Connection Specified Condition
      E5-26 (E2G) - Body ground Below 1 Ω

    NG → See step   7 

    OK → See step   8 

  7. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM) 
    1. Disconnect the E29 MAF meter connector.
    2. Disconnect the E5 ECM connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard resistance

      Tester Connection Specified Condition
      E29-4 (E2G) - E5-26 (E2G) Below 1 Ω
    4. Reconnect the MAF meter connector.
    5. Reconnect the ECM connector.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK → See step   10 

  8. REPLACE MASS AIR FLOW METER. Refer to  REMOVAL 
  9. CHECK ECM POWER SOURCE CIRCUIT. Refer to  ECM Power Source Circuit 
  10. REPLACE ECM. Refer to  REMOVAL