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SFI SYSTEM(w/o Canister Pump Module), Diagnostic DTC:P0102, P0103

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DTC Code DTC Name
P0102 Mass Air Flow Circuit Low
P0103 Mass Air Flow Circuit High
*1 Mass Air Flow Meter Sub-assembly - - *a Silicon Chip Sensor *b By-pass Duct *c Heater *d Heater Thermistor *e Intake Air *f Temperature Sensor (After Heater) *g Temperature Sensor (Before Heater) *h Intake Air Thermistor 1 *i Intake Air Thermistor 2 *j Temperature Sensor (Before Heater) 1 *k Temperature Sensor (After Heater) 2 *l Temperature Sensor (After Heater) 1 *m Temperature Sensor (Before Heater) 2 *n Control Circuit *o Heater Control Bridge Circuit *p Temperature Sensor Bridge Circuit *q Air Flow - -
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DESCRIPTION

The mass air flow meter sub-assembly is a sensor that measures the intake air volume using the following built-in components:


Intake air flows past the temperature sensor (before heater), the heater, and then the temperature sensor (after heater) of the silicon chip sensor in the by-pass duct. As the intake air is warmed up when it is exposed to the heater, the temperature of the intake air as it flows past the temperature sensor (after heater) is higher than when it flows past the temperature sensor (before heater). The difference in temperature of the intake air at each temperature sensor varies depending on the velocity of the intake air that flows past the silicon chip sensor. The temperature sensor bridge circuit detects the difference in temperature and the control circuit converts it into a pulse signal and outputs it to the ECM. When the temperature detected by the temperature sensor (before heater) is higher than that detected by the temperature sensor (after heater), backflow of the intake air is detected.

The ECM calculates the intake air volume based on the pulse signal received from the mass air flow meter sub-assembly, and uses it to determine the fuel injection duration necessary for an optimal air-fuel ratio.

The heater control bridge circuit has a temperature sensor and power transistor, and maintains the heater temperature at a specific temperature.

Tip:

When DTCs is stored, the ECM enters fail-safe mode. During fail-safe mode, the ECM calculates the fuel injection duration based on the engine speed and throttle valve angle. Fail-safe mode continues until a pass condition is detected.

DTC No. Detection Item DTC Detection Condition Trouble Area MIL Memory
P0102 Mass Air Flow Circuit Low

The mass air flow meter sub-assembly output frequency is less than 0.1 kHz for 3 seconds

(1 trip detection logic)

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

  • Mass air flow meter sub-assembly

  • ECM

 Comes on DTC stored
P0103 Mass Air Flow Circuit High

The mass air flow meter sub-assembly output frequency is higher than 9.8 kHz for 3 seconds.

(1 trip detection logic)

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

  • Mass air flow meter sub-assembly

  • ECM

 Comes on DTC stored
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MONITOR DESCRIPTION

If there is a defect or an open or short circuit in the mass air flow meter sub-assembly, the frequency 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 frequency remains less than 0.1 kHz, or higher than 9.8 kHz for 3 seconds, the ECM stores a DTC.

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MONITOR STRATEGY

Frequency of Operation Continuous
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CONFIRMATION DRIVING PATTERN


  1. Connect the GTS to the DLC3.

  2. Turn the engine 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 engine switch off and wait for at least 30 seconds.

  5. Turn the engine switch on (IG) and turn the GTS on.

  6. Wait 5 seconds or more.

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

  8. Read the pending DTCs.

    Tip:

    • 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 / 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
    Tip:

    • 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.

Table 1. *a VCVG *b Mass Air Flow Meter Sub-assembly
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WIRING DIAGRAM

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CAUTION / NOTICE / HINT

Tip:

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.

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PROCEDURE


  1. *a Front view of wire harness connector (to Mass Air Flow Meter Sub-assembly)
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    CHECK TERMINAL VOLTAGE (POWER SOURCE OF MASS AIR FLOW METER SUB-ASSEMBLY)


    1. Disconnect the mass air flow meter sub-assembly 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 Condition Specified Condition
      F39-3 (5V) - Body ground Engine switch on (IG) 4.8 to 5.2 V
      F39-1 (FG) - F39-2 (E2G) Engine switch on (IG) 4.8 to 5.2 V
      Result
      Proceed to
      OK
      NG

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    REPLACE MASS AIR FLOW METER SUB-ASSEMBLY


    1. Replace the mass air flow meter sub-assembly.

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      Tip:

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

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      Result
      Proceed to
      NEXT

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    CHECK IF DTC OUTPUT RECURS (SEE IF DTC P0102 OR P0103 IS OUTPUT AGAIN)


    1. Connect the GTS to the DLC3.

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

    3. Clear the DTCs.

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      1. Powertrain > Engine > Clear DTCs


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

    5. Turn the engine switch on (IG) and turn the GTS on.

    6. Drive the vehicle in accordance with the driving pattern described in the Confirmation Driving Pattern.

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

    8. Read the DTCs.


      1. Powertrain > Engine > Trouble Codes


      Result
      Result Proceed to
      DTC P0102 or P0103 is output A
      DTCs are not output B

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    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
      F1-21 (VCVG) - F39-3 (5V) Always Below 1 Ω
      F1-23 (VG) - F39-1 (FG) Always Below 1 Ω
      F1-24 (E2G) - F39-2 (E2G) Always Below 1 Ω
      F1-21 (VCVG) or F39-3 (5V) - Body ground Always 10 kΩ or higher
      F1-23 (VG) or F39-1 (FG) - Body ground Always 10 kΩ or higher
      F1-24 (E2G) or F39-2 (E2G) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    • OK

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    • NG

      REPAIR OR REPLACE HARNESS OR CONNECTOR