ECD SYSTEM Pre-heating Control Circuit

DESCRIPTION

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

A01CYD0E07

Tech Tips


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

  • After the engine is started, the ECM performs "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.

A01CX5SE06

WIRING DIAGRAM

A01CWGJE01
*a GLOW
*b Glow Plug
*c FL MAIN
*d Battery

CAUTION / NOTICE / HINT

Note


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

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

PROCEDURE


  1. CHECK TERMINAL VOLTAGE (GLOW PLUG RELAY)


    1. A01CYS4C01
      *a

      Front view of wire harness connector

      (to Glow Plug Relay)

      Remove the glow plug relay assembly.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      B38-4 - Body ground Always 11 to 14 V

    3. Reinstall the glow plug relay assembly.

      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GLOW PLUG RELAY - BATTERY)

    OK

  2. INSPECT GLOW PLUG RELAY ASSEMBLY


    1. Inspect the glow plug relay assembly.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE GLOW PLUG RELAY ASSEMBLY

    OK

  3. 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

  4. CHECK GLOW PLUG ASSEMBLY (INSTALLATION)


    1. Check the glow plug installation.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    TIGHTEN GLOW PLUG ASSEMBLY

    OK

  5. CHECK HARNESS AND CONNECTOR (GLOW PLUG - GLOW PLUG RELAY - BODY GROUND)


    1. Remove the glow plug relay assembly.

    2. Disconnect the glow plug connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      B38-3 - B83-1 Always Below 1 Ω
      B38-1 - Body ground Always Below 1 Ω
      B38-3 or B83-1 - Body ground Always 10 kΩ or higher

    4. Reinstall the glow plug relay assembly.

    5. Reconnect the glow plug connector.

      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. CHECK HARNESS AND CONNECTOR (GLOW PLUG RELAY - ECM AND BODY GROUND)

    Result
    Proceed to
    OK
    NG

    1. Remove the glow plug relay assembly.

    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
      B38-2 - B76-58 (GREL) Always Below 1 Ω
      B38-2 or B76-58 (GREL) - Body ground Always 10 kΩ or higher

    4. Reinstall the glow plug relay assembly.

    5. Reconnect the ECM connector.


    OK

    REPLACE ECM Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR