ECD SYSTEM, Diagnostic DTC:P0100

DTC Code DTC Name
P0100 Mass Air Flow Circuit Malfunction

DESCRIPTION

The mass air flow meter assembly consists of a platinum hot wire, temperature sensor and 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 assembly, as it is hardly affected by the resistance of the wire harness.

The internal circuit of the mass air flow meter assembly contains a hot wire and cold wire. 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 1945 and 8500 Hz depending on the air flow rate. The ECM calculates the mass air flow rate based on this frequency.

A207644E05

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Memory

P0100

Mass Air Flow Circuit Malfunction

Mass air flow meter assembly signal frequency is less than 850 Hz with the engine speed at 400 rpm or higher for 3 seconds (1 trip detection logic).

  • Open or short in mass air flow meter assembly circuit

  • Mass air flow meter assembly

  • ECM

Comes on

DTC stored
Table 1. Related Data List

DTC No.

Data List

P0100

MAF
Tip:

  • If DTC P0100 is stored, the following symptoms may appear (as the ECM mistakenly determines that there is less air than the actual intake air amount, EGR is decreased according to the target EGR):

    • Combustion noise increases

CONFIRMATION DRIVING PATTERN

DTC No.

DTC Detection Drive Pattern

P0100

3 seconds after engine is started

WIRING DIAGRAM

A298507E01

CAUTION / NOTICE / HINT

Note:

  • Inspect the fuses of circuits related to this system before performing the following procedure.

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

Tip:

Read freeze frame data using the GTS. 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, and other data from the time the malfunction occurred.

PROCEDURE

  1. CHECK TERMINAL VOLTAGE (POWER SOURCE OF MASS AIR FLOW METER ASSEMBLY)

    1. A127724C03

      *a

      Front view of wire harness connector

      (to Mass Air Flow Meter Assembly)

      Disconnect the mass air flow meter assembly connector.

    2. Turn the ignition switch to ON.

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

      Standard Voltage

      Tester Connection

      Condition

      Specified Condition

      B2-3 (+B) - Body ground

      Ignition switch ON

      11 to 14 V

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTORClick here

    OK

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

    1. Disconnect the mass air flow meter 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

      B2-1 (VG) - B164-65 (VG)

      Always

      Below 1 Ω

      B2-2 (E2G) - B164-64 (EVG)

      Always

      Below 1 Ω

      B2-1 (VG) or B164-65 (VG) - Body ground

      Always

      10 kΩ or higher

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTORClick here

    OK

  3. REPLACE MASS AIR FLOW METER ASSEMBLY

    1. Replace the mass air flow meter assembly.

      Click here

    Result

    Proceed to

    NEXT
    NEXT

  4. CHECK WHETHER DTC OUTPUT RECURS

    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Clear the DTCs.

      Powertrain > Engine and ECT > Clear DTCs

    5. After engine is started for 3 seconds.

    6. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

    7. Read the DTCs.

      Powertrain > Engine and ECT > Trouble Codes

      Result

      Result

      Proceed to

      DTC P0100 is output

      A

      DTC is not output

      B
    B

    END

    A

  5. REPLACE ECM

    1. Replace the ECM.

      Click here

    Result

    Proceed to

    NEXT
    NEXT

    CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIREDClick here

  6. REPAIR OR REPLACE HARNESS OR CONNECTOR

    Tip:

    If the voltage at the mass air flow meter assembly connector is not 11 to 14 V, repair or replace the harness and connector between the mass air flow meter assembly and EFI-MAIN relay (including the EFI NO. 1 fuse).

    1. Repair or replace the harness or connector.

    Result

    Proceed to

    NEXT
    NEXT

  7. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Clear the DTCs.

      Powertrain > Engine and ECT > Clear DTCs

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

    6. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

    7. Confirm that the DTC is not output.

      Powertrain > Engine and ECT > Trouble Codes

    Result

    Proceed to

    NEXT
    NEXT

    END