ECD SYSTEM(w/ DPF) 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 during which current 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 ECM calculated time. The glow plug assembly is then heated, and enhances fuel combustion with a cold engine.

A01VL23E01

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.

A01VGY3E08

WIRING DIAGRAM

Refer to DTC P0380 Click here.

CAUTION / NOTICE / HINT

Note

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

PROCEDURE


  1. INSPECT GLOW PLUG RELAY ASSEMBLY


    1. A01VIOSE06
      Text in Illustration
      *a

      Component without harness connected

      (Glow Plug Relay Assembly)

      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

    NG

    REPLACE GLOW PLUG RELAY ASSEMBLY

    OK

  2. INSPECT GLOW PLUG ASSEMBLY (RESISTANCE)


    1. Inspect the glow plug assembly Click here.


    NG

    REPLACE GLOW PLUG ASSEMBLY Click here

    OK

  3. CHECK GLOW PLUG ASSEMBLY (INSTALLATION)


    1. Check the glow plug assembly installation Click here.


    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
      B76-2 - B21-13 (GREL) Always Below 1 Ω
      B76-2 or B21-13 (GREL) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. CHECK HARNESS AND CONNECTOR (GLOW PLUG RELAY ASSEMBLY - NO. 1 INTEGRATION RELAY)


    1. Remove the No. 1 integration relay from the engine room relay block.

    2. Disconnect the glow plug relay assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      B76-1 - 1E-3 Always Below 1 Ω
      B76-1 or 1E-3 - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. CHECK ECM POWER SOURCE CIRCUIT


    1. Check the ECM power source circuit Click here.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

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


    1. Disconnect the battery positive terminal.

    2. Disconnect the glow plug relay assembly connector.

    3. Disconnect the glow plug wire.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      B76-3 - B75-1 Always Below 1 Ω
      B76-4 - Battery positive terminal Always Below 1 Ω

    OK

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR