SFI SYSTEM, Diagnostic DTC:P0102, P0103

DTC Code DTC Name
P0102 Mass Air Flow Circuit Low
P0103 Mass Air Flow Circuit High

DESCRIPTION

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

The ECM uses this information to determine the fuel injection time and to provide 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 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 provide 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.

A015ZQ0E01
DTC No. DTC Detection Condition Trouble Area
P0102 Open in mass air flow meter circuit for 3 seconds

  • Open in mass air flow meter circuit


  • Short in ground circuit


  • Mass air flow meter


  • ECM
P0103 Short in mass air flow meter circuit for 3 seconds

  • Short in mass air flow meter circuit (+B 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 / Data List / MAF.

Mass Air Flow Rate (g/sec.) Malfunction
Approximately 0.0

  • Open in mass air flow meter power source circuit


  • Open or short in VG circuit
0.78 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 sets a DTC.

Example:

When the sensor output voltage remains 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

A0161ZKE05

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 (MASS AIR FLOW RATE)


    1. Connect the intelligent tester to the DLC3.

    2. Start the engine.

    3. Turn the tester ON.

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

    5. Read the values displayed on the intelligent tester.

      Note

      During the test, do not use the exhaust air duct to perform suction on the exhaust pipe.

      Result
      Mass Air Flow Rate (g/sec.) Proceed to
      0.0 A
      0.78 or more B
      Between 0.0 and 0.78 C

    B

    INSPECT ECM (SENSOR GROUND) Click here

    C

    CHECK FOR INTERMITTENT PROBLEMS Click here

    A

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


    1. A0161I3E14

      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
      E29-3 (+B) - Body ground Engine switch on (IG) 11 to 14 V

    4. Reconnect the mass air flow meter connector.


    NG

    CHECK FUSE (EFI NO. 2 FUSE) Click here

    OK

  3. INSPECT ECM (VG VOLTAGE)


    1. A0161GPE45

      Start the engine.

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

      Tech Tips

      The shift lever should be in P or N and the air conditioning switch should be turned off.

      Standard Voltage
      Tester Connection Condition Specified Condition
      E3-25 (VG) - E3-24 (E2G) Engine idling 0.5 to 3.0 V

    NG

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

    OK

    REPLACE ECM Click here

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


    1. A015Z5FE06

      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
      E29-5 (VG) - E3-25 (VG) Always Below 1 Ω
      E29-4 (E2G) - E3-24 (E2G) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      E29-5 (VG) or E3-25 (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

    REPLACE MASS AIR FLOW METER Click here

  5. CHECK FUSE (EFI NO. 2 FUSE)


    1. A015YXDE06

      Remove the EFI No. 2 fuse from the engine room No. 2 relay block.

    2. Measure the resistance of the EFI No. 2 fuse.

      Standard Resistance
      Tester Connection Condition Specified Condition
      EFI No. 2 fuse Always Below 1 Ω

    3. Reinstall the EFI No. 2 fuse.


    NG

    REPLACE FUSE (EFI NO. 2 FUSE)

    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR (EFI NO. 2 FUSE - MASS AIR FLOW METER)

  6. INSPECT ECM (SENSOR GROUND)


    1. A0161GPE46

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      E3-24 (E2G) - Body ground Always Below 1 Ω

    NG

    REPLACE ECM Click here

    OK

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


    1. A015Z5FE06

      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
      E29-5 (VG) - E3-25 (VG) Always Below 1 Ω
      E29-4 (E2G) - E3-24 (E2G) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      E29-5 (VG) or E3-25 (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

    REPLACE MASS AIR FLOW METER Click here