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СИСТЕМА SFI, Diagnostic DTC:P0102, P0103

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DTC Code DTC Name
P0102 Mass or Volume Air Flow Circuit Low Input
P0103 Mass or Volume Air Flow Circuit High Input
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DESCRIPTION

The mass air flow meter is a sensor that measures the amount of air flowing through the throttle valve.

The ECM uses this information to determine the fuel injection time and to provide the appropriate air-fuel ratio.

Inside the mass air flow meter, there is a heated platinum wire which is exposed to the flow of intake air.

By applying a specific electrical current to the wire, the ECM heats it to a given temperature. The flow of incoming air cools both the wire and an internal thermistor, affecting their resistance. To maintain a constant current value, the ECM varies the voltage applied to the wire and internal thermistor. The voltage level is proportional to the airflow through the sensor, and the ECM uses it to calculate the intake air volume.

The circuit is constructed so that the platinum hot wire and temperature sensor create a bridge circuit, and the power transistor is controlled so that the potentials of A and B remain equal to maintain the predetermined temperature.

Tip:

When either of these DTCs is stored, the ECM enters fail-safe mode. During fail-safe mode, the ignition timing is calculated by the ECM according to the engine speed and throttle valve position. The ECM continues operating in fail-safe mode until a pass condition is detected.

DTC No. DTC Detection Condition Trouble Area
P0102 Mass air flow meter voltage is below 0.2 V for 3 seconds (1 trip detection logic).

  • Open or short in mass air flow meter circuit

  • Mass air flow meter assembly

  • ECM
P0103 Mass air flow meter voltage is higher than 4.9 V for 3 seconds (1 trip detection logic).

  • Open or short in mass air flow meter circuit

  • Mass air flow meter assembly

  • ECM
Tip:

When either of these DTCs is stored, check the air flow rate by entering the following menus: Powertrain / Engine and ECT / Data List / All Data / MAF.

MAF (gm/s) Malfunction
Approximately 0.0

  • Open in mass air flow meter power source circuit

  • Open or short in VG circuit
160.0 or more Open in E2G circuit
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MONITOR DESCRIPTION

If there is a defect in the mass air flow meter or an open or short circuit, the voltage level deviates from the normal operating range. The ECM interprets this deviation as a malfunction in the mass air flow meter and stores a DTC.

Example:

When the sensor output voltage remains at below 0.2 V, or higher than 4.9 V for more than 3 seconds, the ECM stores a DTC.

If the malfunction is not repaired successfully, a DTC is stored 3 seconds after the engine is next started.

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CONFIRMATION DRIVING PATTERN


  1. Turn the engine switch on (IG) and wait for 5 seconds or more.

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WIRING DIAGRAM

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INSPECTION PROCEDURE

Note:

Inspect the fuses for circuits related to this system before performing the following inspection procedure.

Tip:

Read freeze frame data using the GTS. Freeze frame data records the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred.

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PROCEDURE


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    READ DTC OUTPUT


    1. Connect the GTS to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / MAF.

    5. Read the values displayed on the GTS.

      Table 1. Result
      Result Proceed to
      DTC P0102 is output A
      DTC P0103 is output B
      Tip:

      *: The value must change when the throttle valve is opened or closed with the engine running.


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    INSPECT MASS AIR FLOW METER ASSEMBLY (POWER SOURCE VOLTAGE)


    1. Disconnect the mass air flow meter connector.

    2. Turn the engine switch on (IG).

    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      C3-1 (+B) - Body ground Engine switch on (IG) 11 to 14 V
      Table 2. Text in Illustration
      *a

      Front view of wire harness connector

      (to Mass Air Flow Meter Assembly)

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    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
      Tester Connection Condition Specified Condition
      C3-3 (VG) - C54-74 (VG) Always Below 1 Ω
      C3-2 (E2G) - C54-75 (E2G) Always Below 1 Ω
      C3-3 (VG) or C54-74 (VG) - Body ground Always 10 kΩ or higher

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    INSPECT MASS AIR FLOW METER ASSEMBLY


    1. Inspect the mass air flow meter, referring to the On-vehicle Inspection for Mass Air Flow Meter (Click here).

    2. Inspect the mass air flow meter, referring to the Inspection for Mass Air Flow Meter (Click here).

    3. Inspect the function of the mass air flow meter.


      1. Connect the GTS to the DLC3.

      2. Turn the engine switch on (IG).

      3. Turn the GTS on.

      4. Enter the following menus: Powertrain / Engine and ECT / Data List / MAF.

      5. Start the engine.

      6. Check that the MAF value changes when the engine is raced.

        OK
        The reading changes.

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    CHECK HARNESS AND CONNECTOR (SENSOR GROUND)


    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
      C3-2 (E2G) - Body ground Always Below 1 Ω

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    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
      Tester Connection Condition Specified Condition
      C3-3 (VG) - C54-74 (VG) Always Below 1 Ω
      C3-2 (E2G) - C54-75 (E2G) Always Below 1 Ω
      C3-3 (VG) or C54-74 (VG) - Body ground Always 10 kΩ or higher

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    CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - NO. 1 INTEGRATION RELAY)


    1. Disconnect the mass air flow meter connector.

    2. Remove the No. 1 integration relay from the engine room relay block.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      C3-1 (+B) - 1B-4 Always Below 1 Ω
      C3-1 (+B) or 1B-4 - Body ground Always 10 kΩ or higher

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    REPAIR OR REPLACE HARNESS OR CONNECTOR

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    REPLACE MASS AIR FLOW METER ASSEMBLYClick here

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    REPLACE ECMClick here

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    REPLACE NO.1 INTEGRATION RELAY