LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Scion >> 2011 >> xB Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (Diagnostic Codes) (P0010-P0354) >> SFI System >> DTC P0102: Mass or Volume Air Flow Circuit Low Input; DTC P0103: Mass or Volume Air Flow Circuit High Input >> Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

DTC P0102: Mass or Volume Air Flow Circuit Low Input; DTC P0103: Mass or Volume Air Flow Circuit High Input: Procedure

  1. CHECK DTC OUTPUT 
    1. Connect the Techstream to the DLC3.
    2. Turn the ignition switch to ON.
    3. Turn the Techstream on.
    4. Clear the DTCs. Refer to DTC CHECK / CLEAR .
    5. Drive the vehicle in accordance with the driving pattern described in the Confirmation Driving Pattern.
    6. Read DTCs.
      RESULT

      Result Proceed to
      DTC P0102, and/or P0103 are output A
      DTC is not output B

    B → See step   9 

    A: Go to next step 

  2. READ VALUE USING TECHSTREAM (MAF) 
    1. Read the values using the Techstream (MAF).
      NOTE:
      • Turn the ignition switch off.
      • Perform the inspection with the vehicle indoors and on a level surface.
      • Perform the inspection of the mass air flow meter while it is installed to the air cleaner case (installed to the vehicle).
      • During the test, do not use an exhaust air duct on the exhaust tail pipe assembly.
    2. Connect the Techstream to the DLC3.
    3. Turn the ignition switch to ON (do not start the engine).
    4. Turn the Techstream on.
    5. Enter the following menus: Powertrain / Engine and ECT / Data List / MAF.
    6. Wait 30 seconds, and read the values on the tester.
      RESULT

      Result Proceed to
      0.0 gm/sec A
      More than 0.48 gm/sec B

    B → See step   7 

    A: Go to next step 

  3. INSPECT MASS AIR FLOW METER (POWER SOURCE VOLTAGE) 
    Fig 1: Inspect Mass Air Flow Meter (Power Source Voltage)
    GTY312224Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    TEXT IN ILLUSTRATION

    *a Front view of wire harness connector
    (to Mass Air Flow Meter)
    1. Disconnect the mass air flow meter connector.
    2. Turn the ignition switch to ON.
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      B2-3 (+B) - Body ground Ignition switch ON 11 to 14 V
    4. Reconnect the mass air flow meter connector.

    NG → See step   6 

    OK: Go to next step 

  4. 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
      B2-5 (VG) - B33-118 (VG) Always Below 1 Ω
      B2-4 (E2G) - B33-116 (E2G)

      Standard Resistance (Check for Short)

      Tester Connection Condition Specified Condition
      B2-5 (VG) or B33-118 (VG) - Body ground Always 10 kΩ or higher
    4. Reconnect the mass air flow meter connector.
    5. Reconnect the ECM connector.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  5. INSPECT MASS AIR FLOW METER 
    1. Inspect the mass air flow meter, referring to the On-vehicle Inspection for Mass Air Flow Meter. Refer to ON-VEHICLE INSPECTION .
    2. Inspect the mass air flow meter, referring to the Inspection for Mass Air Flow Meter. Refer to INSPECTION .
    3. Connect the Techstream to the DLC3.
    4. Turn the ignition switch to ON.
    5. Turn the Techstream on.
    6. Start the engine.
    7. Enter the following menus: Powertrain / Engine and ECT / Data List / MAF.
    8. Check that the MAF value changes when the engine revs up depressing the accelerator pedal.

      OK

      The MAF value changes according to the engine speed.

    NG → See step   13 

    OK → See step   10 

  6. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - INTEGRATION RELAY) 
    1. Disconnect the mass air flow meter connector.
    2. Remove the integration relay (EFI MAIN relay) from the engine room relay block.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance (Check for Open)

      Tester Connection Condition Specified Condition
      B2-3 (+B) - 1B-4 Always Below 1 Ω

      Standard Resistance (Check for Short)

      Tester Connection Condition Specified Condition
      B2-3 (+B) or 1B-4 - Body ground Always 10 kΩ or higher
    4. Reconnect the mass air flow meter connector.
    5. Reinstall the integration relay.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK → See step   11 

  7. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - GROUND) 
    Fig 2: Check Harness And Connector (Mass Air Flow Meter - Ground)
    GTY314239Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    TEXT IN ILLUSTRATION

    *a Front view of wire harness connector
    (to Mass Air Flow Meter)
    1. Disconnect the mass air flow meter connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      B2-4 (E2G) - Body ground Always Below 1 Ω
    3. Reconnect the mass air flow meter connector.

    NG → See step   8 

    OK → See step   12 

  8. 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
      B2-5 (VG) - B33-118 (VG) Always Below 1 Ω
      B2-4 (E2G) - B33-116 (E2G)

      Standard Resistance (Check for Short)

      Tester Connection Condition Specified Condition
      B2-5 (VG) or B33-118 (VG) - Body ground Always 10 kΩ or higher
    4. Reconnect the mass air flow meter connector.
    5. Reconnect the ECM connector.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK → See step   10 

  9. CHECK FOR INTERMITTENT PROBLEMS. Refer to  CHECK FOR INTERMITTENT PROBLEMS 
  10. REPLACE ECM. Refer to  REMOVAL 
  11. REPAIR OR REPLACE ECM POWER SOURCE CIRCUIT. Refer to  ECM Power Source Circuit 
  12. REPLACE MASS AIR FLOW METER. Refer to  REMOVAL 
  13. REPLACE MASS AIR FLOW METER 
    1. Replace the mass air flow meter. Refer to REMOVAL .

    NEXT: Go to next step 

  14. CHECK WHETHER DTC OUTPUT RECURS 
    1. Connect the Techstream to the DLC3.
    2. Turn the ignition switch to ON.
    3. Turn the Techstream on.
    4. Clear the DTCs. Refer to DTC CHECK / CLEAR .
    5. Drive the vehicle in accordance with the driving pattern described in the Confirmation Driving Pattern.
    6. Read DTCs.
      RESULT

      Result Proceed to
      DTC P0102, and/or P0103 are output A
      DTC is not output B

    B → END 

    A → See step   15 

  15. REPLACE ECM. Refer to  REMOVAL 
scientia non olet · About LEMON Manuals