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 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.

A000RWYE01
DTC No. DTC Detection Condition Trouble Area
P0102

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

(1 trip detection logic: Engine speed is less than 4000 rpm)

(2 trip detection logic: Engine speed is 4000 rpm or more)*

  • Open or short in mass air flow meter circuit

  • Mass air flow meter

  • ECM
P0103

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

(1 trip detection logic: Engine speed is less than 4000 rpm)

(2 trip detection logic: Engine speed is 4000 rpm or more)*

  • Open or short in mass air flow meter circuit

  • Mass air flow meter

  • ECM

*: w/ Canister Pump Module

Tech Tips

When any of these DTCs are set, check the air flow rate by entering the following menus on the GTS: Powertrain / Engine and ECT / Data List / 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 sets a DTC.

Example:

When the sensor output voltage remains less than 0.2 V, or more than 4.9 V, for 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.

MONITOR STRATEGY

Duration 3 seconds

CONFIRMATION DRIVING PATTERN


A000RREE13

  1. Connect the GTS to the DLC3.

  2. Turn the power switch on (IG) and turn the GTS on.

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

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

  5. Turn the power switch on (IG) and turn the GTS on [A].

  6. Put the engine in inspection mode (maintenance mode) Click here.

  7. Start the engine.

  8. Idle the engine for 5 seconds [B].

  9. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes [C].

  10. 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.

  11. During normal driving, increase the vehicle speed to 80 km/h (50 mph) [D].

    CAUTION:

    When performing the confirmation driving pattern, obey all speed limits and traffic laws.

  12. Depress the accelerator pedal fully to increase the vehicle speed to between 100 and 120 km/h (62 and 75 mph) (engine speed of 4000 rpm or more) and then maintain the speed for at least 5 seconds [E].

    CAUTION:

    When performing the confirmation driving pattern, obey all speed limits and traffic laws.

  13. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes [F].

  14. 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.

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

  16. Input the DTC: P0102 or P0103.

  17. 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 ABNORMAL, the system has a malfunction.

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

    • If the judgment result shows INCOMPLETE or N/A, perform steps [B] through [F] again.



  1. Connect the GTS to the DLC3.

  2. Turn the power switch on (IG) and turn the GTS on.

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

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

  5. Turn the power switch on (IG) 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.

    Tester 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

A000SF4E01

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. READ DTC OUTPUT


    1. Connect the GTS to the DLC3.

    2. Turn the power switch on (IG).

    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 HARNESS AND CONNECTOR (POWER SOURCE VOLTAGE)


    1. A000Q12E01
      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 power switch on (IG).

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      F39-3 (+B) - Body ground Power switch on (IG) 11 to 14 V

    4. Reconnect the mass air flow meter connector.


    NG

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

    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
      Tester Connection Condition Specified Condition
      F39-5 (VG) - F5-98 (VG) Always Below 1 Ω
      F39-4 (E2G) - F5-130 (E2G) Always Below 1 Ω
      F39-5 (VG) or F5-98 (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 GTS to the DLC3.

      2. Turn the power switch on (IG).

      3. Turn the GTS on.

      4. Put the engine in inspection mode (maintenance mode) Click here.

      5. Start the engine.

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

      7. Check that the reading of 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 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
      F39-4 (E2G) - Body ground Always Below 1 Ω

    3. Reconnect the mass air flow meter connector.


    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
      F39-4 (E2G) - F5-130 (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)

  7. 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 No. 1 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
      F39-3 (+B) - 1E-15 Always Below 1 Ω
      F39-3 (+B) or 1E-15 - Body ground Always 10 kΩ or higher

    OK

    REPLACE NO. 1 INTEGRATION RELAY

    NG

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