ECD SYSTEM(w/ Glow Plug Controller), Diagnostic DTC:P0100

DTC Code DTC Name
P0100 Mass Air Flow Circuit

DESCRIPTION

The mass air flow meter 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.

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

A01M3E1C02
*1 Mass Air Flow Meter - -
*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 - -
DTC No. Detection Item DTC Detection Condition Trouble Area MIL Memory
P0100 Mass Air Flow Circuit Mass air flow meter signal frequency is less than 850 Hz with the engine speed at 400 rpm or higher for 3 seconds (2 trip detection logic).

  • Open or short in mass air flow meter circuit

  • Mass air flow meter

  • ECM

 Comes on DTC stored
DTC Detection Drive Pattern
DTC No. DTC Detection Drive Pattern
P0100 3 seconds after engine is started
Related Data List
DTC No. Data List
P0100 MAF

Tech Tips


  • 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

WIRING DIAGRAM

A01LW86E01
*a VCVG
*b Mass Air Flow Meter Assembly

CAUTION / NOTICE / HINT

Note


  • When replacing the ECM, perform ECM Initialization and Registration.

    Click here

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

Tech Tips


  • When the ECM must be replaced, before replacing the ECM, perform the "Learning Values Save" function using the GTS. Then after installing a new ECM, perform all of the initialization and registration procedures for the "Learning Values Write" function by following the instructions shown on the GTS display.

  • 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)

    A01M18TC01
    *a

    Front view of wire harness connector

    (to Mass Air Flow Meter)

    1. Disconnect the mass air flow meter 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
      B187-3 (VCC) - B187-2 (E2G) Ignition switch ON 4.8 to 5.2 V
      B187-1 (FG) - B187-2 (E2G) Ignition switch ON 4.8 to 5.2 V
      Result
      Proceed to
      OK
      NG

    NG

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

    OK

  2. REPLACE MASS AIR FLOW METER


    1. Replace the mass air flow meter.

      Click here

      Result
      Proceed to
      NEXT

    NEXT

    GO TO STEP 4 Click here

  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
      B187-3 (VCC) - B212-99 (VCVG) Always Below 1 Ω
      B187-1 (FG) - B212-97 (VG) Always Below 1 Ω
      B187-2 (E2G) - B212-100 (EVG) Always Below 1 Ω
      B187-3 (VCC) or B212-99 (VCVG) - Body ground and other terminals Always 10 kΩ or higher
      B187-1 (FG) or B212-97 (VG) - Body ground and other terminals Always 10 kΩ or higher
      B187-2 (E2G) or B212-100 (EVG) - Body ground and other terminals Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR Click here

    OK

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

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

    7. Read the pending 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

    GO TO STEP 7 Click here

  6. REPAIR OR REPLACE HARNESS OR CONNECTOR


    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 / Pending.

    7. Confirm that the pending DTC is not output.


      Powertrain > Engine and ECT > Trouble Codes
      Result
      Proceed to
      NEXT

    NEXT

    END