SFI SYSTEM ECM Power Source Circuit

DESCRIPTION

When the power switch is turned on (IG), the auxiliary battery voltage is applied to terminal IGSW of the ECM. The ECM MREL output signal causes a current to flow to the coil, closing the contacts of the No. 1 integration relay (EFI MAIN1 relay) and supplying power to terminal +B and +B2 of the ECM.

If the power switch is turned off, the ECM holds the No. 1 integration relay (EFI MAIN1 relay) ON for a maximum of 2 seconds to allow for the initial setting of the throttle valve.

When the power switch is turned on (IG), voltage from the ECM's MREL terminal is applied to the No. 1 integration relay (EFI MAIN1 relay). This causes the contacts of the No. 1 integration relay (EFI MAIN1 relay) to close, which supplies power to terminal +B and +B2 of the ECM.

WIRING DIAGRAM

A000NMOE03

CAUTION / NOTICE / HINT

Note

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

PROCEDURE


  1. CHECK NO. 1 INTEGRATION RELAY (POWER SOURCE)


    1. A000S4FE02
      Text in Illustration
      *a

      Front view of wire harness connector

      (to No. 1 Integration Relay)

      Remove the No. 1 integration relay from the No. 1 engine room relay block and junction block assembly.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      1D-1 - Body ground Always 11 to 14 V

    3. Reinstall the No. 1 integration relay.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (AUXILIARY BATTERY - NO. 1 INTEGRATION RELAY)

    OK

  2. INSPECT NO. 1 INTEGRATION RELAY (EFI MAIN1 RELAY, IG2 RELAY)


    1. Inspect the No. 1 integration relay Click here.


    NG

    REPLACE NO. 1 INTEGRATION RELAY

    OK

  3. CHECK HARNESS AND CONNECTOR (EFI MAIN1 RELAY - ECM, BODY GROUND)


    1. Remove the No. 1 integration relay from the No. 1 engine room relay block and junction block 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
      1F-9 - A20-2 (+B) Always Below 1 Ω
      1F-10 - A20-3 (+B2) Always Below 1 Ω
      1E-6 - A20-46 (MREL) Always Below 1 Ω
      1F-6 - A20-32 (IGSW) Always Below 1 Ω
      1F-1 - Body ground Always Below 1 Ω
      1F-9 or A20-2 (+B) - Body ground Always 10 kΩ or higher
      1F-10 or A20-3 (+B2) - Body ground Always 10 kΩ or higher
      1E-6 or A20-46 (MREL) - Body ground Always 10 kΩ or higher
      1F-6 or A20-32 (IGSW) - Body ground Always 10 kΩ or higher

    4. Reinstall the No. 1 integration relay.

    5. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. 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
      F5-49 (E1) - Body ground Always Below 1 Ω

    3. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. INSPECT ECM (IGSW VOLTAGE)


    1. Disconnect the ECM connector.

    2. Turn the power switch on (IG).

    3. A000P7HE02
      Text in Illustration
      *a

      Front view of wire harness connector

      (to ECM)

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      A20-32 (IGSW) - Body ground Power switch on (IG) 11 to 14 V

    OK

    REPLACE ECM Click here

    NG

    GO TO SMART ACCESS SYSTEM WITH PUSH-BUTTON START Click here