SFI SYSTEM, 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 meter sub-assembly is a sensor that measures the amount of air flowing through the throttle valve. The ECM uses this information to determine fuel injection duration and to provide an appropriate air fuel ratio.

Inside the mass air flow meter sub-assembly, 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 specific 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 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 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. Fail-safe mode continues until a pass condition is detected.

A005HFEE06
*1 Temperature Sensor (Thermistor)
*2 Power Transistor
*3 Platinum Hot Wire (Heater)
*4 Output Voltage
DTC No. DTC Detection Condition Trouble Area
P0102 The mass air flow meter sub-assembly voltage is less than 0.2 V for 3 seconds (1 trip detection logic)

  • Open or short in mass air flow meter sub-assembly circuit

  • Mass air flow meter sub-assembly

  • No. 1 integration relay

  • ECM
P0103 The mass air flow meter sub-assembly voltage is higher than 4.9 V for 3 seconds (1 trip detection logic)

  • Open or short in mass air flow meter sub-assembly circuit

  • Mass air flow meter sub-assembly

  • No. 1 integration relay

  • 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 sub-assembly power source circuit

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

MONITOR DESCRIPTION

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

Example:

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

MONITOR STRATEGY

Frequency of Operation Continuous

CONFIRMATION DRIVING PATTERN


  1. Connect the GTS to the DLC3.

  2. Turn the ignition switch to ON and turn the GTS on.

  3. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).

  4. Turn the ignition switch off and wait for at least 30 seconds.

  5. Turn the ignition switch to ON and turn the GTS on.

  6. Wait 5 seconds or more.

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

  8. Read the pending DTCs.

    Tech Tips


    • If a pending DTC is output, the system is malfunctioning.

    • If a pending DTC is not output, perform the following procedure.

  9. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

  10. Input the DTC: P0102 or P0103.

  11. Check the DTC judgment result.

    GTS Display Description
    NORMAL

    • DTC judgment completed

    • System normal
    ABNORMAL

    • DTC judgment completed

    • System abnormal
    INCOMPLETE

    • DTC judgment not completed

    • Perform driving pattern after confirming DTC enabling conditions
    N/A

    • Unable to perform DTC judgment

    • Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

    Tech Tips


    • If the judgment result shows NORMAL, the system is normal.

    • If the judgment result shows ABNORMAL, the system has a malfunction.

    • If the judgment result shows INCOMPLETE or N/A, perform the Confirmation Driving Pattern and check the DTC judgment result again.

WIRING DIAGRAM

A005JG9E02

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. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. 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. CHECK DTC OUTPUT (DTC P0102 OR P0103)


    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 the DTCs.

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

    B

    CHECK HARNESS AND CONNECTOR (SENSOR GROUND) Click here

    A

  2. CHECK TERMINAL VOLTAGE (POWER SOURCE OF MASS AIR FLOW METER SUB-ASSEMBLY)


    1. A005JZIE01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Mass Air Flow Meter Sub-assembly)

      Disconnect the mass air flow meter sub-assembly 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 Condition Specified Condition
      B72-1 (+B) - Body ground Ignition switch ON 11 to 14 V

    NG

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

    OK

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


    1. Disconnect the mass air flow meter sub-assembly 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
      B72-3 (VG) - B23-91 (VG) Always Below 1 Ω
      B72-2 (E2G) - B23-92 (E2G) Always Below 1 Ω
      B72-3 (VG) or B23-91 (VG) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. INSPECT MASS AIR FLOW METER SUB-ASSEMBLY


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

    2. Inspect the mass air flow meter sub-assembly, referring to the Inspection for Mass Air Flow Meter Click here.

    3. Inspect the function of the mass air flow meter sub-assembly.


      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 / All Data / MAF.

      5. Start the engine.

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

        OK
        The reading changes.

        Tech Tips

        Perform "Inspection After Repair" after replacing the mass air flow meter sub-assembly Click here.


    OK

    REPLACE ECM Click here

    NG

    REPLACE MASS AIR FLOW METER SUB-ASSEMBLY Click here

  5. CHECK HARNESS AND CONNECTOR (SENSOR GROUND)


    1. Disconnect the mass air flow meter sub-assembly 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

      Tech Tips

      Perform "Inspection After Repair" after replacing the mass air flow meter sub-assembly Click here.


    OK

    REPLACE MASS AIR FLOW METER SUB-ASSEMBLY Click here

    NG

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


    1. Disconnect the mass air flow meter sub-assembly 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

    OK

    REPLACE ECM Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

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


    1. Disconnect the mass air flow meter sub-assembly connector.

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

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      B72-1 (+B) - 1E-3 Always Below 1 Ω
      B72-1 (+B) or 1E-3 - Body ground Always 10 kΩ or higher

    OK

    REPLACE NO. 1 INTEGRATION RELAY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR