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.

A01HV6ME05
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: Engine speed is less than 4000 rpm)

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

  • 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: Engine speed is less than 4000 rpm)

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

  • 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 output, check the air flow rate using the Techstream. Enter the following menus: Powertrain / Engine and ECT / Data List / Primary / 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

Related DTCs

P0102: Mass air flow meter range check (low voltage)

P0103: Mass air flow meter range check (high voltage)
Required Sensors/Components (Main) Mass air flow meter sub-assembly
Required Sensors/Components (Related) Crankshaft position sensor
Frequency of Operation Continuous
Duration 3 seconds
MIL Operation

Immediate: Engine speed less than 4000 rpm

2 driving cycles: Engine speed 4000 rpm or higher
Sequence of Operation None

TYPICAL ENABLING CONDITIONS

Monitor runs whenever the following DTCs are not stored None

TYPICAL MALFUNCTION THRESHOLDS

P0102
Mass air flow meter voltage Less than 0.2 V
P0103
Mass air flow meter voltage Higher than 4.9 V

COMPONENT OPERATING RANGE

Mass air flow meter voltage 0.2 to 4.9 V

CONFIRMATION DRIVING PATTERN

A01HVK0E06

  1. Connect the Techstream to the DLC3.

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

    Techstream 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 steps [B] through [F] again.

  18. If no pending DTC is output, perform a universal trip and check for permanent DTCs Click here.

    Tech Tips


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

    • If no permanent DTC is output, the system is normal.

WIRING DIAGRAM

A01HVSKE02

INSPECTION PROCEDURE

Note

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

Tech Tips

Read freeze frame data using the Techstream. 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 OUTPUT DTC (DTC P0102 OR P0103)


    1. Connect the Techstream to the DLC3.

    2. Turn the power switch on (IG).

    3. Turn the Techstream 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)

    A01HUF4E72
    Text in Illustration
    *a

    Front view of wire harness connector

    (to Mass Air Flow Meter Sub-assembly)

    1. Disconnect the mass air flow meter sub-assembly 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 Condition Specified Condition
      E14-3 (+B) - Body ground Power switch on (IG) 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
      E14-5 (VG) - E28-91 (VG) Always Below 1 Ω
      E14-4 (E2G) - E28-92 (E2G) Always Below 1 Ω
      E14-5 (VG) or E28-91 (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 Techstream to the DLC3.

      2. Turn the power switch on (IG).

      3. Turn the Techstream 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 / Primary / MAF.

      7. 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.


    NG

    REPLACE MASS AIR FLOW METER SUB-ASSEMBLY Click here

    OK

    REPLACE ECM 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
      E14-4 (E2G) - Body ground Always Below 1 Ω

      Tech Tips

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


    NG

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

    OK

    REPLACE MASS AIR FLOW METER SUB-ASSEMBLY Click here

  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
      E14-4 (E2G) - E28-92 (E2G) Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE ECM Click here

  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
      E14-3 (+B) - 1A-8 Always Below 1 Ω
      E14-3 (+B) or 1A-8 - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE NO. 1 INTEGRATION RELAY Click here