ECD SYSTEM (w/ EGR Cooler Bypass Valve), 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 consists of a platinum hot wire, a temperature sensor and a control circuit installed in a plastic housing. The temperature sensor (located in the intake air by-pass of the housing) detects the intake air temperature.

There is little variation in the output from the mass air flow meter, as it is hardly affected by the resistance of the wire harness.

The internal circuit of the mass air flow meter contains a hot wire and temperature sensor. A voltage is output through a bridge circuit (refer to the illustration) indicating the cooling of the hot wire according to the intake air amount. This voltage is then converted into a periodic signal by the periodic signal conversion circuit and output to the ECM. The frequency varies between approximately 1,945 to 8,500 Hz depending on the air flow rate. The ECM calculates the mass air flow rate based on this frequency.

A01KGJ0E01
DTC No. DTC Detection Condition Trouble Area
P0102

MAF meter frequency is less than 850 Hz with the engine speed at 5,000 rpm or less for 3 seconds.

(1 trip detection logic)

  • Open or short in Mass Air Flow (MAF) meter circuit

  • Mass air flow meter

  • EFI3 fuse

  • ECM
P0103

MAF meter frequency is more than 9,800 Hz with the engine speed at 5,000 rpm or less for 3 seconds.

(1 trip detection logic)

  • Open or short in Mass Air Flow (MAF) meter circuit

  • Mass air flow meter

  • ECM

Tech Tips


  • If DTC P0102 is stored, the following symptoms may appear (as the ECU mistakenly determines that there is less air than the actual intake air amount, EGR is decreased according to the target EGR):


    • Combustion noise worsens

  • If DTC P0103 is stored, the following symptoms may appear (as the ECU mistakenly determines that there is more air than the actual intake air amount, EGR is increased according to the target EGR):


    • Misfire

    • White smoke

    • Black smoke

WIRING DIAGRAM

A01KFEUE01

INSPECTION PROCEDURE

Note

After replacing the ECM, the new ECM needs registration Click here and initialization Click here.

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 running or stopped, if the engine was warmed up or not, and other data from the time the malfunction occurred.

PROCEDURE


  1. INSPECT MASS AIR FLOW METER (POWER SOURCE CIRCUIT)

    A01KHV6E96
    Text in Illustration
    *1 Mass Air Flow Meter
    *a Wire Harness Side

    1. Disconnect the A25 mass air flow meter connector.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A25-3 (+B) - Body ground Ignition switch ON 11 to 14 V

    3. Reconnect the mass air flow meter connector.


    NG

    CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - R/B NO. 2) Click here

    OK

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


    1. Disconnect the A25 mass air flow meter connector.

    2. Disconnect the E13 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
      A25-5 (VG) - E13-17 (VG) Always Below 1 Ω
      A25-4 (E2G) - E13-18 (EVG) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      A25-5 (VG) or E13-17 (VG) - Body ground Always 10 kΩ or higher

    4. Reconnect the mass air flow meter connector.

    5. Reconnect the ECM connector.


    OK

    REPLACE MASS AIR FLOW METER Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR Click here

  3. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - R/B NO. 2)


    1. Inspect the EFI3 fuse.


      1. Remove the EFI3 fuse from the R/B No. 2.

      2. Check the EFI3 fuse resistance.

        Standard resistance
        Below 1 Ω

      3. Reinstall the EFI3 fuse.

    2. Disconnect the A25 mass air flow meter connector.

    3. Remove the EFI MAIN relay from the R/B No. 2.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      A25-3 (+B) - 3 (EFI MAIN relay) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      A25-3 (+B) or 3 (EFI MAIN relay) - Body ground Always 10 kΩ or higher

    5. Reconnect the mass air flow meter connector.

    6. Reinstall the EFI MAIN relay.


    OK

    CHECK ECM POWER SOURCE CIRCUIT Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR Click here

  4. REPAIR OR REPLACE HARNESS OR CONNECTOR


    1. Repair or replace the harness or connector.


    NEXT

    CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED Click here

  5. CHECK ECM POWER SOURCE CIRCUIT


    1. Check the ECM power source circuit Click here.


    NEXT

    CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED Click here

  6. REPLACE MASS AIR FLOW METER


    1. Replace the mass air flow meter Click here.


    NEXT

  7. CHECK WHETHER DTC OUTPUT RECURS


    1. Connect the intelligent tester to the DLC3.

    2. Clear DTCs Click here.

    3. After engine is started for 3 seconds.

    4. Select the following menus: Powertrain / Engine and ECT / DTC.

    5. Read DTCs.

      Result
      Result Proceed to
      P0102 or P0103 A
      No output B

    B

    END

    A

  8. REPLACE ECM


    1. Replace the ECM Click here.


    NEXT

  9. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED


    1. Connect the intelligent tester to the DLC3.

    2. Clear DTCs Click here.

    3. Start the engine and wait for 3 seconds or more.

    4. Select the following menus: Powertrain / Engine and ECT / DTC.

    5. Confirm that the DTC is not output again.


    NEXT

    END