ECD SYSTEM(w/o Glow Plug Controller) Pre-heating Control Circuit

DESCRIPTION

The glow plug assemblies are mounted inside the engine combustion chamber. To ensure efficient engine starting with a cold engine, the ECM calculates a time interval during which current needs to flow through the glow plug assemblies, depending on the starting engine coolant temperature when the ignition switch is turned to ON. The ECM then turns on the glow plug relay assembly and permits the current to flow through the glow plug assemblies based on the ECM calculated time. The glow plug assemblies are then heated, and enhances fuel combustion with a cold engine.

A01TCUUE01

Tech Tips


  • These troubleshooting procedures are for: 1) difficult engine starting in cold weather, and 2) difficulty driving/vehicle malfunctions in cold weather immediately after engine is started.

  • After the engine is started, the ECM performs an "after-glow" for a certain period of time. In proportion to the actual engine coolant temperature, the time period varies. The after-glow reduces diesel engine knocking, white smoke emissions and engine noises when the engine is cold.

  • Pre-glow time depends on battery voltage and engine coolant temperature.

  • After-glow time depends on atmospheric pressure and engine coolant temperature.

WIRING DIAGRAM

A01T8JUE01

CAUTION / NOTICE / HINT

Note


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

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

    Click here

  • After turning ignition switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) battery terminal notices before proceeding with work.

    Click here

PROCEDURE


  1. INSPECT GLOW PLUG RELAY ASSEMBLY

    A01T9JEC02
    *a

    Component without harness connected

    (Glow Plug Relay Assembly)

    1. Disconnect the glow plug relay assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      3 - 4 Battery voltage not applied 10 kΩ or higher
      Battery voltage applied to terminals 1 - 2 Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE GLOW PLUG RELAY ASSEMBLY

    OK

  2. INSPECT GLOW PLUG ASSEMBLY (RESISTANCE)


    1. Inspect the glow plug assembly.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE GLOW PLUG ASSEMBLY Click here

    OK

  3. CHECK GLOW PLUG ASSEMBLY (INSTALLATION)


    1. Check the glow plug assembly installation.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    TIGHTEN GLOW PLUG ASSEMBLY Click here

    OK

  4. CHECK HARNESS AND CONNECTOR (GLOW PLUG RELAY ASSEMBLY - ECM)


    1. Disconnect the glow plug relay 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
      A100-2 - B138-13 (GREL) Always Below 1 Ω
      A100-2 or B138-13 (GREL) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. CHECK HARNESS AND CONNECTOR (GLOW PLUG RELAY ASSEMBLY - EFI-MAIN RELAY)


    1. Disconnect the glow plug relay 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
      A100-1 - Body ground Ignition switch ON 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. CHECK ECM POWER SOURCE CIRCUIT


    1. Check the ECM power source circuit.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  7. CHECK HARNESS AND CONNECTOR (GLOW PLUG RELAY ASSEMBLY - GLOW PLUG ASSEMBLY - BATTERY)


    1. Disconnect the negative (-) battery terminal.

    2. Disconnect the positive (+) battery terminal.

    3. Disconnect the glow plug relay assembly connector.

    4. Disconnect the glow plug wire.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A100-3 - B128-1 Always Below 1 Ω
      A100-4 - Battery positive terminal Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE ECM Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR