ECD SYSTEM(w/o DPF), Diagnostic DTC:P0102, P0103

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

DESCRIPTION

The Mass Air Flow (MAF) 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 MAF 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 the cold film element 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.

Tech Tips

When any of these DTCs are set, the ECM enters fail-safe mode. During fail-safe mode, the ignition timing is calculated by the ECM, according to the engine RPM and throttle valve position. Fail-safe mode continues until a pass condition is detected.

B001WW7E01
P0102
DTC Detection Drive Pattern DTC Detection Condition Trouble Area
Ignition switch ON for 3 seconds MAF meter voltage is 0.2 V or less with the engine speed at 4000 rpm or less for 3 seconds (1 trip detection logic).

  • Open in Mass Air Flow (MAF) meter circuit

  • Mass air flow meter

  • ECM
P0103
DTC Detection Drive Pattern DTC Detection Condition Trouble Area
Ignition switch ON for 3 seconds MAF meter voltage is 4.9 V or more with the engine speed at 4000 rpm or less for 3 seconds (1 trip detection logic).

  • Shot in Mass Air Flow (MAF) meter circuit

  • Mass air flow meter

  • ECM
Related Data List
DTC No. Data List
P0102 MAF
P0103

Tech Tips


  • If DTC P0102 or P0103 is stored, the following symptoms may appear (as the ECU mistakenly determines that there is less air than the actual intake air amount, EGR is decreased to match the target EGR):


    • Combustion noise worsens

  • If DTC P0102 or P0103 is stored, the following symptoms may appear (as the ECU mistakenly determines that there is more air than the actual intake air amount, EGR is increased to match the target EGR):


    • Misfire

    • White smoke

    • Black smoke

  • After confirming DTC P0102 or P0103, check the mass air flow ratio by entering the following menus: Powertrain / Engine and ECT / Data List / MAF.

    Mass Air Flow Rate (gm/sec) Malfunction
    Approximately 0.0

    • Open in Mass Air Flow (MAF) meter power source circuit

    • Open or short in VG circuit
    174.0 or more Open in E2G circuit

MONITOR DESCRIPTION

If there is a defect in the MAF 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 MAF meter and sets a DTC.

Example:

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

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

WIRING DIAGRAM

B001Z1BE12

CAUTION / NOTICE / HINT

Note

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

Tech Tips

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.

PROCEDURE


  1. READ DTC OUTPUT


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

    5. Read DTCs.

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

    B

    CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM) Click here

    A

  2. INSPECT MASS AIR FLOW METER (POWER SOURCE VOLTAGE)

    B001XX4E01
    *1 Front view of wire harness connector: (to Mass Air Flow Meter)

    1. Disconnect the MAF 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
      C50-1 (+B) - Body ground Ignition switch ON 11 to 14 V

    NG

    CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - INTEGRATION RELAY) Click here

    OK

  3. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)


    1. Disconnect the MAF meter connector.

    2. Disconnect the ECM connector.

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

      Standard Resistance
      for LHD
      Tester Connection Condition Specified Condition
      C50-3 (VG) - C45-119 (VG) Always Below 1 Ω
      C50-2 (E2G) - C45-94 (EVG) Always Below 1 Ω
      C50-3 (VG) or C45-119 (VG) - Body ground Always 10 kΩ or higher
      for RHD
      Tester Connection Condition Specified Condition
      C50-3 (VG) - C46-119 (VG) Always Below 1 Ω
      C50-2 (E2G) - C46-94 (EVG) Always Below 1 Ω
      C50-3 (VG) or C46-119 (VG) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. INSPECT MASS AIR FLOW METER


    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 ignition switch to ON.

      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.

    OK

    REPLACE ECM Click here

    NG

    REPLACE MASS AIR FLOW METER Click here

  5. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - INTEGRATION RELAY)


    1. Disconnect the MAF meter connector.

    2. Remove the 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
      C50-1 (+B) - 1S-7 Always Below 1 Ω
      C50-1 (+B) or 1S-7 - Body ground Always 10 kΩ or higher

    OK

    CHECK ECM POWER SOURCE CIRCUIT Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  6. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)


    1. Disconnect the MAF meter connector.

    2. Disconnect the ECM connector.

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

      Standard Resistance
      for LHD
      Tester Connection Condition Specified Condition
      C50-3 (VG) - C45-119 (VG) Always Below 1 Ω
      C50-2 (E2G) - C45-94 (EVG) Always Below 1 Ω
      C50-3 (VG) or C45-119 (VG) - Body ground Always 10 kΩ or higher
      for RHD
      Tester Connection Condition Specified Condition
      C50-3 (VG) - C46-119 (VG) Always Below 1 Ω
      C50-2 (E2G) - C46-94 (EVG) Always Below 1 Ω
      C50-3 (VG) or C46-119 (VG) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  7. CHECK HARNESS AND CONNECTOR (SENSOR GROUND)

    B001WT0E01
    *1 Front view of wire harness connector: (to Mass Air Flow Meter)

    1. Disconnect the MAF meter connector.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      C50-2 (E2G) - Body ground Always Below 1 Ω

    OK

    REPLACE MASS AIR FLOW METER Click here

    NG

    REPLACE ECM Click here