ECD SYSTEM > ECM Power Source Circuit

for Preparation Click here


DESCRIPTION

When the ignition switch is turned ON, the 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 MAIN relay and supplying power to terminal +B of the ECM.

WIRING DIAGRAM


A111093E01


INSPECTION PROCEDURE

NOTICE:
If the ECM is replaced, the new ECM needs initialization (Click here).

1.CHECK ECM TERMINAL VOLTAGE (+B TERMINAL)


    A018294E34

  1. Turn the ignition switch ON.

  1. Measure the voltage of the ECM connectors.

    Standard voltage:
    Tester Connection
    		Specified Condition
    E5-1 (+B) - E7-7 (E1)
    		9 to 14 V



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


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


    A065745E08

  1. Disconnect the E7 ECM connector.

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

    Standard resistance:
    Tester Connection
    		Specified Condition
    E7-7 (E1) - Body ground
    		Below 1 Ω



NG
REPAIR OR REPLACE HARNESS AND CONNECTOR
OK


3.CHECK ECM TERMINAL VOLTAGE (IGSW TERMINAL)


    A018294E35

  1. Turn the ignition switch ON.

  1. Measure the voltage of the ECM connectors.

    Standard voltage:
    Tester Connection
    		Specified Condition
    E5-9 (IGSW) - E7-7 (E1)
    		9 to 14 V



OK
Go to step 6
NG


4.INSPECT FUSE (IGN FUSE)


    F050101E01

  1. Remove the IGN fuse from the instrument panel J/B.

  1. Measure the resistance of the fuse.

    Standard resistance:
    Below 1 Ω



NG
CHECK FOR SHORT IN ALL HARNESS AND COMPONENTS CONNECTED TO FUSE, AND REPLACE FUSE
OK


5.INSPECT IGNITION SWITCH ASSEMBLY


    A056879E16

  1. Disconnect the I9 ignition switch connector.

  1. Measure the resistance of the ignition switch.

    Standard resistance:
    Tester Connection
    		Switch Condition
    		Specified Condition
    5 (AM2) - 6 (IG2)
    		LOCK
    		10 kΩ or higher
    5 (AM2) - 6 (IG2)
    		ON
    		Below 1 Ω



NG
REPLACE IGNITION SWITCH ASSEMBLY
OK


6.CHECK ECM TERMINAL VOLTAGE (MREL TERMINAL)


    A018294E36

  1. Turn the ignition switch ON.

  1. Measure the voltage of the ECM connectors.

    Standard voltage:
    Tester Connection
    		Specified Condition
    E5-8 (MREL) - E7-7 (E1)
    		9 to 14 V



NG
REPLACE ECM
OK


7.INSPECT FUSE (EFI FUSE)


    A099789E09

  1. Remove the EFI fuse from the engine room J/B.

  1. Measure the resistance of the fuse.

    Standard resistance:
    Below 1 Ω



NG
CHECK FOR SHORT IN ALL HARNESS AND COMPONENTS CONNECTED TO FUSE, AND REPLACE FUSE
OK


8.INSPECT INTEGRATION RELAY (MAIN RELAY)


    G039047E07

  1. Remove the integration relay from the engine room J/B (Click here).

  1. Disconnect the 1J integration relay connector.

  1. Measure the voltage of the MAIN relay.

    Standard voltage:
    Tester Connection
    		Condition
    		Specified Condition
    1J-4 - Body ground
    		Ignition switch ON
    		10 to 14 V



NG
REPLACE ECM
OK


9.CHECK HARNESS AND CONNECTOR (MAIN RELAY - ECM)


    G034918E02

  1. Disconnect the 1J integration relay connector from the engine room J/B (Click here).

  1. Disconnect the E5 ECM connector.

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

    Standard resistance:
    Tester Connection
    		Specified Condition
    1J-4 - E5-1 (+B)
    		Below 1 Ω
    1J-4 or E5-1 (+B) - Body ground
    		10 kΩ or higher



NG
REPAIR OR REPLACE HARNESS AND CONNECTOR (MAIN RELAY - ECM)
OK

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