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Home >> Lexus >> 2010 >> RX 450h 3.5 C >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control (Diagnostic Codes (P0010-P0125) >> SFI System >> DTC P0102: Mass or Volume Air Flow Circuit Low Input; DTC P0103: Mass or Volume Air Flow Circuit High Input (To 08/2009) >> 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 (To 08/2009): Procedure

  1. READ DTC OUTPUT 
    1. Connect the Techstream to the DLC3.
    2. Turn the power switch on (IG).
    3. Turn the Techstream on.
    4. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
    5. Read the DTCs.

      Result

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

    B → See step   5 

    A: Go to next step 

  2. CHECK HARNESS AND CONNECTOR (POWER SOURCE VOLTAGE) 
    1. Disconnect the mass air flow meter sub-assembly connector.
      Fig 1: Checking Harness And Connector (Power Source Voltage) Terminals
      GTY284736Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Turn the power switch on (IG).
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      D3-3 (+B) - Body ground Power switch on (IG) 11 to 14 V
      TEXT IN ILLUSTRATION

      *1 Front view of wire harness connector
      (to Mass Air Flow Meter Sub-assembly)
    4. Reconnect the mass air flow meter sub-assembly connector.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - EFI MAIN RELAY) 

    OK: Go to next step 

  3. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - ECM) 
    1. Disconnect the mass air flow meter sub-assembly connector.
      Fig 2: Checking Harness And Connector (Mass Air Flow Meter Sub-Assembly - ECM) Terminals
      GTY263170Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    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
      D3-5 (VG) - D1-121 (VG) Always Below 1 Ω
      D3-4 (E2G) - D1-120 (E2G) Always Below 1 Ω

      Standard Resistance (Check for Short)

      Tester Connection Condition Specified Condition
      D3-5 (VG) or D1-121 (VG) - Body ground Always 10 kΩ or higher
      TEXT IN ILLUSTRATION

      *1 Front view of wire harness connector
      (to Mass Air Flow Meter Sub-assembly)      		 *2 Front view of wire harness connector
      (to ECM)
    4. Reconnect the mass air flow meter sub-assembly connector.
    5. Reconnect the ECM connector.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - ECM) 

    OK: Go to next step 

  4. INSPECT MASS AIR FLOW METER SUB-ASSEMBLY 
    1. Perform On-vehicle Inspection. Refer to ON-VEHICLE INSPECTION .
      Fig 3: Identifying Mass Air Flow Meter Sub-Assembly
      GTY175998Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Perform Inspection. Refer to INSPECTION .
    3. Inspect the function of the mass air flow meter sub-assembly.
      1. Remove the mass air flow meter sub-assembly with the connector connected.
      2. Connect the Techstream to the DLC3.
      3. Turn the power switch on (IG).
      4. Turn the Techstream on.
      5. Enter the following menus: Powertrain / Engine and ECT / Data List / MAF.
      6. Blow air to the mass air flow meter sub-assembly and check that the intake air amount reading changes.

        OK

        The reading changes.

    NG → See step   7 

    OK → See step   8 

  5. CHECK HARNESS AND CONNECTOR (SENSOR GROUND) 
    1. Disconnect the mass air flow meter sub-assembly connector.
      Fig 4: Checking Harness And Connector (Sensor Ground) Terminal
      GTY286200Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance (Check for Open)

      Tester Connection Condition Specified Condition
      D3-4 (E2G) - Body ground Always Below 1 Ω
      TEXT IN ILLUSTRATION

      *1 Front view of wire harness connector
      (to Mass Air Flow Meter Sub-assembly)
    3. Reconnect the mass air flow meter sub-assembly connector.

    NG → See step   6 

    OK → See step   7 

  6. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - ECM) 
    1. Disconnect the mass air flow meter sub-assembly connector.
      Fig 5: Checking Harness And Connector (Mass Air Flow Meter Sub-Assembly - ECM) Terminals
      GTY262484Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    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
      D3-4 (E2G) - D1-120 (E2G) Always Below 1 Ω
      TEXT IN ILLUSTRATION

      *1 Front view of wire harness connector
      (to Mass Air Flow Meter Sub-assembly)      		 *2 Front view of wire harness connector
      (to ECM)
    4. Reconnect the mass air flow meter sub-assembly connector.
    5. Reconnect the ECM connector.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - ECM) 

    OK → See step   8 

  7. REPLACE MASS AIR FLOW METER SUB-ASSEMBLY. Refer to  REMOVAL 
  8. REPLACE ECM. Refer to  REMOVAL 
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