ECD SYSTEM ECM Power Source Circuit

DESCRIPTION

When the engine switch is turned to on (IG), 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

B003N92E06

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. B003QLJC25
      *a

      Component with harness connected

      (ECM)

      Turn the engine switch on (IG).

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      G50-2 (+B) - C41-1 (E1) Engine switch on (IG) 11 to 14 V
      G50-3 (+B2) - C41-1 (E1) Engine switch on (IG) 11 to 14 V
      G50-4 (+B3) - C41-1 (E1) Engine switch on (IG) 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
      C41-1 (E1) - Body ground Always Below 1 Ω

    3. Reconnect the ECM connector.

      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. INSPECT ECM (IGSW VOLTAGE)


    1. B003QLJC26
      *a

      Component with harness connected

      (ECM)

      Turn the engine switch on (IG).

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      G50-18 (IGSW) - C41-1 (E1) Engine switch on (IG) 11 to 14 V
      Result
      Proceed to
      OK
      NG

    NG

    INSPECT IG2 RELAY Click here

    OK

  4. INSPECT ECM (MREL VOLTAGE)


    1. B003QLJC27
      *a

      Component with harness connected

      (ECM)

      Turn the engine switch on (IG).

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      G49-14 (MREL) - C41-1 (E1) Engine switch on (IG) 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).

      Result
      Proceed to
      OK
      NG

    NG

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

    OK

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


    1. Remove the instrument panel junction block 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 - G50-2 (+B) Always Below 1 Ω
      2G-5 - G50-3 (+B2) Always Below 1 Ω
      2G-5 - G50-4 (+B3) Always Below 1 Ω
      2P-8 - G49-14 (MREL) Always Below 1 Ω
      2K-3 - Body ground Always Below 1 Ω
      2G-5 or G50-2 (+B) - Body ground and other terminals Always 10 kΩ or higher
      2G-5 or G50-3 (+B2) - Body ground and other terminals Always 10 kΩ or higher
      2G-5 or G50-4 (+B3) - Body ground and other terminals Always 10 kΩ or higher
      2P-8 or G49-14 (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)

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  7. INSPECT IG2 RELAY


    1. Inspect the IG2 relay.

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE IG2 RELAY

    OK

  8. 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
      G50-18 (IGSW) - IG2 Relay terminal 3 Always Below 1 Ω
      G50-18 (IGSW) or IG2 Relay terminal 3 - Body ground and other terminals Always 10 kΩ or higher

    4. Reconnect the ECM connector.

    5. Reinstall the IG2 relay.

      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  9. CHECK TERMINAL VOLTAGE (IG2 RELAY)


    1. B003PXKC01
      *1 Instrument Panel Relay Block No. 4

      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

  10. 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
      G16-20 (IG1D) - IG2 Relay terminal 1 Always Below 1 Ω
      IG2 Relay terminal 2 - Body ground Always Below 1 Ω
      G16-20 (IG1D) or IG2 Relay terminal 1 - Body ground and other terminals Always 10 kΩ or higher

    4. Reconnect the certification ECU (smart key ECU assembly) connector.

    5. Reinstall the IG2 relay.

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR