SFI SYSTEM > ECM Power Source Circuit

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DESCRIPTION

When the ignition switch is turned ON, battery voltage is applied to terminal IGSW of the ECM. The ECM "MREL" output signal causes a current to flow to the MAIN relay coil, closing the contacts of the MAIN relay and supplying power to terminal +B of the ECM.

WIRING DIAGRAM


A114423E01


INSPECTION PROCEDURE

1.INSPECT ECM (+B VOLTAGE)
G035614E30

  1. Turn the ignition switch ON.

  1. Measure the voltage of the ECM connectors.
    Standard voltage: 
    Tester Connection
    		Specified Condition
    E14-1 (+B) - E17-1 (E1)
    		9 to 14 V



OK
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
NG


2.CHECK WIRE HARNESS (ECM - BODY GROUND)
A112688E01

  1. Disconnect the E17 ECM connector.

  1. Measure the resistance of the wire harness side connector.
    Standard resistance: 
    Tester Connection
    		Specified Condition
    E17-1 (E1) - Body ground
    		Below 1 Ω



NG
REPAIR OR REPLACE HARNESS AND CONNECTOR
OK


3.INSPECT ECM (IGSW VOLTAGE)
G035614E31

  1. Turn the ignition switch ON.

  1. Measure the voltage of the ECM connectors.
    Standard voltage 
    Tester Connection
    		Specified Condition
    E14-9 (IGSW) - E17-1 (E1)
    		9 to 14 V



OK
Go to step 6
NG


4.INSPECT FUSE (IGN)
G034718E02

  1. Remove the IGN fuse from the instrument panel junction block.

  1. Measure the resistance of the fuse.

    Standard resistance:
    Below 1 Ω



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


5.INSPECT IGNITION OR STARTER SWITCH ASSEMBLY
A112426E02

  1. Disconnect the I6 ignition switch connector.

  1. Measure the resistance of the switch.
    Standard resistance: 
    Tester Connection
    		Switch Condition
    		Specified Condition
    5 (AM2) - 6 (IG2)
    		OFF
    		10 kΩ or higher
    5 (AM2) - 6 (IG2)
    		ON
    		Below 1 Ω



NG
REPLACE IGNITION OR STARTER SWITCH ASSEMBLY
OK

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

6.INSPECT ECM (MREL VOLTAGE)
G035614E32

  1. Turn the ignition switch ON.

  1. Measure the voltage of the ECM connectors.
    Standard voltage: 
    Tester Connection
    		Specified Condition
    E14-8 (MREL) - E17-1 (E1)
    		9 to 14 V



NG
REPLACE ECM
OK


7.INSPECT FUSE (EFI)
A113025E02

  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


8.INSPECT INTEGRATION RELAY (MAIN RELAY)
G034717E05

  1. Disconnect the integration relay from the engine room junction block.

  1. Measure the voltage of the integration relay.
    Standard voltage: 
    Tester Connection
    		Condition
    		Specified Condition
    1J-4 - Body ground
    		Ignition switch ON
    		10 to 14 V



NG
REPLACE INTEGRATION RELAY
OK


9.CHECK WIRE HARNESS (INTEGRATION RELAY- ECM, INTEGRATION RELAY - BODY GROUND)
A112689E01

  1. Disconnect the 1J integration relay connector from the engine room junction block.

  1. Disconnect the E14 ECM connector.

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

    Standard resistance:
    Tester Connection
    		Specified Condition
    1J-2 - E14-8 (MREL)
    		Below 1 Ω
    1J-4 - E14-1 (+B)
    		Below 1 Ω
    1J-3 - Body ground
    		Below 1 Ω
    1J-2 or E14-8 (MREL) - Body ground
    		10 kΩ or higher
    1J-4 or E14-1 (+B) - Body ground
    		10 kΩ or higher



NG
REPAIR OR REPLACE HARNESS AND CONNECTOR
OK

REPAIR OR REPLACE HARNESS AND CONNECTOR (ECM - BATTERY POSITIVE TERMINAL)