SFI SYSTEM > ECM Back-up Power Source Circuit

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DESCRIPTION

While the ignition switch is OFF, battery voltage is supplied to terminal BATT of the ECM for the DTC memory, air-fuel ratio adaptive control value memory, etc.

WIRING DIAGRAM


A094237E05


INSPECTION PROCEDURE

1.INSPECT FUSE (EFI)
G034719E06

  1. Remove the EFI fuse from the engine room junction block.

  1. Measure the resistance of the fuse.

    Standard resistance:
    Below 1 Ω



NG
CHECK FOR SHORT IN ALL HARNESSES AND COMPONENTS CONNECTED TO FUSE
OK


2.CHECK ECM (BATT VOLTAGE)
A066060E25

  1. Turn the ignition switch ON.

  1. Measure the voltage of the ECM connectors.

    Standard voltage:
    Tester Connection
    		Specified Condition
    E9-3 (BATT) - E12-3 (E1)
    		8 to 14 V



OK
REPLACE ECM
NG


3.CHECK WIRE HARNESS (ECM - EFI FUSE, EFI FUSE - BATTERY)
G034712E03

  1. Check the wire harness between the EFI fuse and ECM.

    1. Remove the EFI fuse from the engine room junction block.

    2. Disconnect the E9 ECM connector.

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

      Standard resistance:
      Tester Connection
      		Specified Condition
      J/B EFI fuse terminal 2 - E9-3 (BATT)
      		Below 1 Ω
      J/B EFI fuse terminal 2 or E9-3 (BATT) - Body ground
      		10 kΩ or higher

  1. Check the wire harness between the EFI fuse and battery.

    1. Remove the EFI fuse from the engine room junction block.

    2. Disconnect the positive (+) battery cable.

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

      Standard resistance:
      Tester Connection
      		Specified Condition
      Positive (+) battery cable - J/B EFI fuse terminal 1
      		Below 1 Ω
      Positive (+) battery cable or J/B EFI fuse terminal 1 -
      Body ground
      		10 kΩ or higher



NG
REPAIR OR REPLACE HARNESS AND CONNECTOR
OK

REPLACE ENGINE ROOM RELAY BLOCK