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 ON. The ECM then turns on the GLOW relay and permits the current to flow through the glow plug based on the ECM's calculated time. The GLOW relay is then heated, and enhances fuel combustion with a cold engine.

This DTC will be set if the glow plug or the circuit is open.

A01BGBGE01

Tech Tips


  • These troubleshooting procedures are for: 1) difficult starting engine 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.

A01BA5WE01

WIRING DIAGRAM

A01BD7OE01

INSPECTION PROCEDURE

Note

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

PROCEDURE


  1. INSPECT GLOW RELAY


    1. A01BH7M

      Remove the GLOW relay from the engine room R/B.

    2. Measure the resistance of the relay.

      Standard resistance
      Tester Connection Specified Condition
      3 - 5 10 kΩ or higher
      3 - 5

      Below 1 Ω

      (when battery voltage is applied to terminals 1 and 2)

    NG

    REPLACE GLOW RELAY

    OK

  2. INSPECT GLOW FUSE


    1. A01BI5DE01

      Remove the GLOW fuse from the engine room J/B and R/B No.1.

    2. Measure the resistance of the fuse.

      Standard resistance
      Below 1 Ω

    NG

    CHECK FOR SHORT IN ALL HARNESS AND COMPONENTS CONNECTED TO FUSE, AND REPLACE FUSE

    OK

  3. INSPECT GLOW PLUG ASSEMBLY (RESISTANCE)


    1. A01BAU1

      Disconnect the glow plug wire.

    2. Measure the resistance of the glow plugs.

      Standard resistance
      Tester Connection Condition Specified Condition
      Glow plug terminal - Body ground 20°C (68°F) Approximately 0.95 Ω

      Tech Tips

      If any of the glow plugs has an open malfunction, the engine power is insufficient only when the engine is cold.

      Note


      • Exercise extreme care not to damage the glow plug pipes. Damaging them could cause an open circuit, or shorten the life of the glow plugs.

      • Keep the glow plugs free of oil and fuel while cleaning.

      • Wipe any oil off of the terminal and Bakelite washer with a clean, dry cloth during inspection.

      • Do not apply more than 11 V to the glow plugs as it may cause an open circuit.


    NG

    REPLACE GLOW PLUG ASSEMBLY

    OK

  4. CHECK GLOW PLUG ASSEMBLY (INSTALLATION)


    1. Check the glow plug installation.

      OK
      Glow plugs are installed securely.
      Torque:
      13 N*m  { 130 kgf*cm, 10 ft.*lbf }

    NG

    TIGHTEN GLOW PLUG

    OK

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


    1. A01BEA6E02

      Disconnect the B9 ECM connector.

    2. Remove the GLOW relay from the engine room R/B.

    3. Measure the resistance of the wire harness side connectors.

      Standard resistance
      Tester Connection Specified Condition
      B9-15 (GREL) - R/B GLOW relay terminal 2 Below 1 Ω
      R/B GLOW relay terminal 1 - Body ground Below 1 Ω
      B9-15 (GREL) - Body ground 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS AND CONNECTOR

    OK

  6. CHECK HARNESS AND CONNECTOR (GLOW PLUG - GLOW RELAY, BATTERY - GLOW RELAY)


    1. A01BHMEE01

      Remove the GLOW relay from the engine room R/B.

    2. Disconnect the D53 glow plug connector.

    3. Measure the resistance of the wire harness side connectors.

      Standard resistance
      Tester Connection Specified Condition
      R/B GLOW relay terminal 3 - Glow plug wire connector Below 1 Ω
      R/B GLOW relay terminal 5 - Positive (+) battery terminal cabled Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS AND CONNECTOR

    OK

  7. CHECK ECM TERMINAL VOLTAGE (GREL TERMINAL)


    1. A01BF68E12

      Start the engine.

    2. Measure the voltage of the ECM connectors.

      Standard voltage
      Tester Connection Condition Specified Condition
      B9-15 (GREL) - D1-28 (E2) Engine coolant temperature 40°C (104°F) or less 9 to 14 V

    NG

    REPLACE ECM

    OK

  8. CHECK ECM TERMINAL VOLTAGE (BATT TERMINAL)


    1. A01BDCLE01

      Measure the voltage of the ECM connectors.

      Standard voltage
      Tester Connection Specified Condition
      B7-2 (BATT) - D3-7 (E1) 9 to 14 V

    NG

    REPAIR OR REPLACE HARNESS AND CONNECTOR

    OK

    CHECK FOR INTERMITTENT PROBLEMS