Ecd System Ecm Power Source Circuit

Engine. Lexus Is250, Is220D. Gse20 Ale20
2Ad-Fhv Engine Control System. Lexus Is250, Is220D. Gse20 Ale20

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND)

CHECK ECM TERMINAL VOLTAGE (IGSW TERMINAL)

INSPECT FUSE (IGN FUSE)

CHECK TERMINAL VOLTAGE (EFI MAIN RELAY TERMINAL)

INSPECT FUSE (ECD FUSE)

INSPECT EFI MAIN RELAY

CHECK HARNESS AND CONNECTOR (MAIN RELAY - ECM)

ECD SYSTEM - ECM Power Source Circuit


DESCRIPTION

When the engine switch is turned ON (IG), 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


Lexus Is250, Is220D. Gse20 Ale20.2Ad-Fhv Engine Control System.Ecd System.Ecd System Ecm Power Source Circuit


INSPECTION PROCEDURE

NOTICE:
After replacing the ECM, the new ECM needs registration (Click here) and initialization (Click here).
1.CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND)


    Lexus Is250, Is220D. Gse20 Ale20.2Ad-Fhv Engine Control System.Ecd System.Ecd System Ecm Power Source Circuit

  1. Disconnect the E59 ECM connector.

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

    Standard resistance:
    Tester Connection
    		Specified Condition
    E1 (E59-109) - Body ground
    		Below 1 Ω


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


2.CHECK ECM TERMINAL VOLTAGE (IGSW TERMINAL)


    Lexus Is250, Is220D. Gse20 Ale20.2Ad-Fhv Engine Control System.Ecd System.Ecd System Ecm Power Source Circuit

  1. Disconnect the A49 ECM connector.

  1. Turn the engine switch ON (IG).

  1. Measure the voltage of the ECM connectors.

    Standard voltage:
    Tester Connection
    		Specified Condition
    IGSW (A49-25) - Body ground
    		9 to 14 V


OK
Go to step 4
NG


3.INSPECT FUSE (IGN FUSE)


    Lexus Is250, Is220D. Gse20 Ale20.2Ad-Fhv Engine Control System.Ecd System.Ecd System Ecm Power Source Circuit

  1. Remove the IGN fuse from the cowl side J/B LH.

  1. Measure the resistance of the fuse.

    Standard resistance:
    Below 1 Ω


NG
REPLACE FUSE
OK

CHECK AND REPLACE SMART ACCESS SYSTEM WITH PUSH-BUTTON START

4.CHECK TERMINAL VOLTAGE (EFI MAIN RELAY TERMINAL)


    Lexus Is250, Is220D. Gse20 Ale20.2Ad-Fhv Engine Control System.Ecd System.Ecd System Ecm Power Source Circuit

  1. Remove the EFI MAIN relay from the engine room J/B and R/B No. 2.

  1. Turn the engine switch ON (IG).

  1. Measure the voltage.

    Standard voltage:
    Tester Connection
    		Specified Condition
    EFI MAIN relay (1) - Body ground
    		9 to 14 V


NG
Go to step 7
OK


5.INSPECT FUSE (ECD FUSE)


    Lexus Is250, Is220D. Gse20 Ale20.2Ad-Fhv Engine Control System.Ecd System.Ecd System Ecm Power Source Circuit

  1. Remove the ECD fuse from the engine room J/B and R/B No. 2.

  1. Measure the resistance of the fuse.

    Standard resistance:
    Below 1 Ω


NG
REPLACE FUSE
OK


6.INSPECT EFI MAIN RELAY


    Lexus Is250, Is220D. Gse20 Ale20.2Ad-Fhv Engine Control System.Ecd System.Ecd System Ecm Power Source Circuit

  1. Remove the EFI MAIN relay from the engine room R/B No. 2.

  1. Inspect the EFI MAIN relay.

    Standard resistance:
    Tester Connection
    		Specified Condition
    3 - 5
    		10 kΩ or higher
    Below 1 Ω
    (Apply battery voltage to terminals 1 and 2)

  1. Reinstall the EFI MAIN relay.



NG
REPLACE ECM
OK


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


    Lexus Is250, Is220D. Gse20 Ale20.2Ad-Fhv Engine Control System.Ecd System.Ecd System Ecm Power Source Circuit

  1. Check the harness and connector between the EFI MAIN relay and ECM.

    1. Remove the EFI MAIN relay from the engine room J/B and R/B No. 2.

    2. Disconnect the A49 ECM connector.

    3. Check the resistance between the wire harness side connectors.

      Standard resistance (Check for open):
      Tester Connection
      		Specified Condition
      EFI MAIN relay (1) - MREL (A49-45)
      		Below 1 Ω
      Standard resistance (Check for short):
      Tester Connection
      		Specified Condition
      EFI MAIN relay (1) or MREL (A49-45) - Body ground
      		10 kΩ or higher

    4. Reconnect the ECM connector.

  1. Check the harness and connector between the EFI MAIN relay and body ground.

    1. Remove the EFI MAIN relay from the engine room J/B and R/B No. 2.

    2. Check the resistance between the wire harness side connector and body ground.

      Standard resistance (Check for open):
      Tester Connection
      		Specified Condition
      EFI MAIN relay (2) - Body ground
      		Below 1 Ω

    3. Reinstall the EFI MAIN relay.



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

REPLACE ECM