ECD SYSTEM(w/ Urea SCR System) ECM Power Source Circuit

DESCRIPTION

When the ignition switch is turned to ON, the battery voltage is applied to terminal IGSW of the ECM. The MREL output signal from ECM causes a current to flow to the coil, closing the contacts of the EFI-MAIN NO. 1 relay and supplying power to terminal +B of the ECM.

WIRING DIAGRAM

Figure 1. w/ Entry and Start System

B0027BBE09

Figure 2. w/o Entry and Start System

B0026WFE15

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. INSPECT ECM (+B VOLTAGE)


    1. B00291KC13
      *a

      Component with harness connected

      (ECM)

      Turn the ignition switch to ON.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      G86-2 (+B) - C60-1 (E1) Ignition switch ON 11 to 14 V
      G86-3 (+B2) - C60-1 (E1) Ignition switch ON 11 to 14 V
      G86-4 (+B3) - C60-1 (E1) Ignition switch ON 11 to 14 V
      Result
      Proceed to
      OK
      NG

    OK

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

    NG

  2. CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND)


    1. Disconnect the ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      C60-1 (E1) - Body ground Always Below 1 Ω
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. INSPECT ECM (IGSW VOLTAGE)


    1. B00291KC14
      *a

      Component with harness connected

      (ECM)

      Turn the ignition switch to ON.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      G86-18 (IGSW) - C60-1 (E1) Ignition switch ON 11 to 14 V
      Result
      Proceed to
      OK
      NG (w/ Entry and Start System)
      NG (w/o Entry and Start System)

    NG (w/o Entry and Start System)

    INSPECT IGNITION SWITCH ASSEMBLY Click here

    NG (w/ Entry and Start System)

    INSPECT IG2 RELAY Click here

    OK

  4. INSPECT ECM (MREL VOLTAGE)


    1. B00291KC15
      *a

      Component with harness connected

      (ECM)

      Turn the ignition switch to ON.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      G86-14 (MREL) - C60-1 (E1) Ignition switch ON 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    REPLACE ECM Click here

    OK

  5. INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY (EFI-MAIN NO. 1 RELAY)


    1. Inspect the instrument panel junction block assembly (EFI-MAIN NO. 1 relay).

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

    OK

  6. CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - ECM, INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - BODY GROUND)


    1. Remove the instrument panel junction block 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
      2G-5 - G86-2 (+B) Always Below 1 Ω
      2G-5 - G86-3 (+B2) Always Below 1 Ω
      2G-5 - G86-4 (+B3) Always Below 1 Ω
      2P-8 - G85-14 (MREL) Always Below 1 Ω
      2K-3 - Body ground Always Below 1 Ω
      2G-5 or G86-2 (+B) - Body ground and other terminals Always 10 kΩ or higher
      2G-5 or G86-3 (+B2) - Body ground and other terminals Always 10 kΩ or higher
      2G-5 or G86-4 (+B3) - Body ground and other terminals Always 10 kΩ or higher
      2P-8 or G85-14 (MREL) - Body ground and other terminals Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  7. INSPECT IGNITION SWITCH ASSEMBLY


    1. Inspect the ignition switch assembly.

      Click here

      Result
      Proceed to
      OK
      NG

    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - IGNITION SWITCH ASSEMBLY, IGNITION SWITCH ASSEMBLY - ECM)

    NG

    REPLACE IGNITION SWITCH ASSEMBLY Click here

  8. INSPECT IG2 RELAY


    1. Inspect the IG2 relay.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE IG2 RELAY

    OK

  9. CHECK HARNESS AND CONNECTOR (NO. 4 INSTRUMENT PANEL RELAY BLOCK - ECM)


    1. Disconnect the ECM connector.

    2. Remove the IG2 relay from No. 4 instrument panel relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G86-18 (IGSW) - IG2 relay terminal 3 Always Below 1 Ω
      G86-18 (IGSW) or IG2 relay terminal 3 - Body ground and other terminals Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  10. CHECK TERMINAL VOLTAGE (IG2 RELAY)


    1. Remove the IG2 relay from No. 4 instrument panel relay block.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      IG2 relay terminal 5 - Body ground Always 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  11. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - NO. 4 INSTRUMENT PANEL RELAY BLOCK)


    1. Disconnect the certification ECU (smart key ECU assembly) connector.

    2. Remove the IG2 relay from No. 4 instrument panel relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G69-20 (IG1D) - IG2 relay terminal 1 Always Below 1 Ω
      IG2 relay terminal 2 - Body ground Always Below 1 Ω
      G69-20 (IG1D) or IG2 relay terminal 1 - Body ground and other terminals Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    OK

    CHECK ENTRY AND START SYSTEM Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR