ECD SYSTEM Pre-heating Control Circuit

DTC Code DTC Name
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.

A129368E07
Tip:

  • 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.

A117830E06

WIRING DIAGRAM

A284168E01

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. A131566C01

      *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