SFI SYSTEM, Diagnostic DTC:P0100, P0102, P0103

DTC Code DTC Name
P0100 Mass or Volume Air Flow Circuit
P0102 Mass or Volume Air Flow Circuit Low Input
P0103 Mass or Volume Air Flow Circuit High Input

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 these components in the mass air flow meter. The voltage level is proportional to the air flow 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 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.

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 speed and throttle valve position. Fail-safe mode continues until a pass condition is detected.

A005HFEE05
*1 Temperature Sensor (Thermistor)
*2 Power Transistor
*3 Platinum Hot Wire (Heater)
*4 Output Voltage
DTC No. DTC Detection Condition Trouble Area
P0100

Mass air flow meter voltage less than 0.2 V, or more than 4.9 V for 0.3 seconds

(1 trip detection logic)

  • Open or short in mass air flow meter circuit

  • Mass air flow meter

  • ECM
P0102

Mass air flow meter voltage less than 0.2 V for 3 seconds

(1 trip detection logic)

  • Open or short in mass air flow meter circuit

  • Mass air flow meter

  • ECM
P0103

Mass air flow meter voltage more than 4.9 V for 3 seconds

(1 trip detection logic)

  • Open or short in mass air flow meter circuit

  • Mass air flow meter

  • ECM

Tech Tips

When any of these DTCs are set, check the air-flow rate by entering the following menus: Powertrain / Engine and ECT / Data List / All Data / MAF.

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

  • Open in mass air flow meter power source circuit

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

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 below 0.2 V, or higher than 4.9 V for more than 3 seconds, the ECM stores a DTC.

CONFIRMATION DRIVING PATTERN


  1. Turn the ignition switch to ON and wait for 5 seconds or more.

WIRING DIAGRAM

A005MEUE03

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 intelligent tester. 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 VALUE USING INTELLIGENT TESTER (MAF)


    1. Connect the intelligent tester to the DLC3.

    2. Start the engine.

    3. Enter the following menus: Powertrain / Engine and ECT / MAF.

    4. Read the values displayed on the tester.

      Result
      Result Proceed to
      Mass air flow rate is 0.0 gm/sec A
      Mass air flow rate is 271.0 gm/sec or more B
      Mass air flow rate is between 1.0 gm/sec and 270.0 gm/sec (*1) C

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


    B

    CHECK HARNESS AND CONNECTOR (SENSOR GROUND) Click here

    C

    CHECK FOR INTERMITTENT PROBLEMS Click here

    A

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


    1. A005LRCE01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Mass air flow meter)

      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
      B72-1 (+B) - Body ground Ignition switch ON 11 to 14 V

    4. Reconnect the mass air flow meter connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (NO. 1 INTEGRATION RELAY - MASS AIR FLOW METER)

    OK

  3. 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
      B72-3 (VG) - B23-91 (VG) Always Below 1 Ω
      B72-2 (E2G) - B23-92 (E2G) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      B72-3 (VG) or B23-91 (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 (MASS AIR FLOW METER - ECM)

    OK

  4. INSPECT MASS AIR FLOW METER


    1. Perform On-vehicle Inspection Click here.

    2. Perform Inspection Click here.

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


      1. Connect the intelligent tester to the DLC3.

      2. Turn the ignition switch to ON.

      3. Turn the tester on.

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

      5. Start the engine.

      6. Check that the reading of the mass air flow meter changes when the engine is raced.

        OK
        The reading changes.

      Tech Tips

      Perform "Inspection After Repairs" after replacing the mass air flow meter Click here.


    OK

    REPLACE ECM Click here

    NG

    REPLACE MASS AIR FLOW METER Click here

  5. 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
      B72-2 (E2G) - Body ground Always Below 1 Ω

    3. Reconnect the mass air flow meter connector.

      Tech Tips

      Perform "Inspection After Repairs" after replacing the mass air flow meter Click here.


    OK

    REPLACE MASS AIR FLOW METER Click here

    NG

  6. 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
      B72-2 (E2G) - B23-92 (E2G) Always Below 1 Ω

    4. Reconnect the mass air flow meter connector.

    5. Reconnect the ECM connector.


    OK

    REPLACE ECM Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (MASS AIR FLOW METER - ECM)