ECM Power Source Circuit 2ZR-FXE

ECM Power Source Circuit

Description

Wiring diagram

Inspection procedure

Check harness and connector (ecm - body ground)

Inspect ecm (igsw voltage)

Inspect no. 2 integration relay (efi main relay)

Check harness and connector (no. 2 integration relay (efi main relay) - ecm)

Check harness and connector (no. 2 integration relay (efi main relay) - auxiliary battery)

Check harness and connector (no. 2 integration relay (efi main relay) - body ground)

Inspect no. 2 integration relay (ig2 relay)

Check harness and connector (no. 2 integration relay (ig2 relay) - ecm)

Check harness and connector (no. 2 integration relay (ig2 relay) - auxiliary battery)

Check harness and connector (no. 2 integration relay (ig2 relay) - body ground)

Check harness and connector (power management control ecu - integration relay (ig2 relay))

Description

When the power switch is turned on (IG), auxiliary battery voltage is applied to IGSW of the ECM. The output signal from the MREL terminal of the ECM causes a current to flow to the coil, closing the contacts of the No. 2 integration relay (EFI MAIN relay) and supplying power to either terminal +B and +B2 of the ECM.

Wiring diagram

Lexus ECM Power Source Circuit Description

Inspection procedure

NOTICE:

  1. After turning the power switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work .
  2. Inspect the fuses for circuits related to this system before performing the following inspection procedure.

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

  1. Disconnect the ECM connector.

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

    Standard Resistance:

    Tester Connection Condition Specified Condition
    D27-104 (E1) - Body ground Always Below 1 ?
  NG  
REPAIR OR REPLACE HARNESS OR CONNECTOR
 
OK  
   

2.INSPECT ECM (IGSW VOLTAGE)

Lexus ECM Power Source Circuit. Disconnect the ECM connector.

  1. Disconnect the ECM connector.

  1. Turn the power switch on (IG).

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

    Standard Voltage:

    Tester Connection Switch Condition Specified Condition
    A60-28 (IGSW) - Body ground Power switch on (IG) 11 to 14 V
    Text in Illustration
    *a Front view of wire harness connector (to ECM)
  NG  
Go to step 7
 
OK  
   

3.INSPECT NO. 2 INTEGRATION RELAY (EFI MAIN RELAY)

  1. Inspect the No. 2 integration relay (EFI MAIN relay) .

  NG  
REPLACE NO. 2 INTEGRATION RELAY
 
OK  
   

4.CHECK HARNESS AND CONNECTOR (NO. 2 INTEGRATION RELAY (EFI MAIN RELAY) - ECM)

  1. Remove the No. 2 integration relay (EFI MAIN relay) from the engine room relay block.

  1. Disconnect the No. 2 integration relay connector.

  1. Disconnect the ECM connector.

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

    Standard Resistance:

    Tester Connection Condition Specified Condition
    1B-4 - A60-1 (+B2) Always Below 1 ?
    1B-4 - A60-2 (+B) Always Below 1 ?
    1B-2 - A60-6 (MREL) Always Below 1 ?
    1B-4 or A60-1 (+B2) - Body ground Always 10 k? or higher
    1B-4 or A60-2 (+B) - Body ground Always 10 k? or higher
    1B-2 or A60-6 (MREL) - Body ground Always 10 k? or higher
  NG  
REPAIR OR REPLACE HARNESS OR CONNECTOR
 
OK  
   

5.CHECK HARNESS AND CONNECTOR (NO. 2 INTEGRATION RELAY (EFI MAIN RELAY) - AUXILIARY BATTERY)

  1. Remove the No. 2 integration relay (EFI MAIN relay) from the engine room relay block.

  1. Disconnect the No. 2 integration relay connector.

  1. Disconnect the negative (-) auxiliary battery terminal.

  1. Disconnect the positive (+) auxiliary battery terminal.

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

    Standard Resistance:

    Tester Connection Condition Specified Condition
    1C-1 - Positive (+) auxiliary battery terminal Always Below 1 ?
    1C-1 or Positive (+) auxiliary battery terminal - Body ground Always 10 k? or higher
  NG  
REPAIR OR REPLACE HARNESS OR CONNECTOR
 
OK  
   

6.CHECK HARNESS AND CONNECTOR (NO. 2 INTEGRATION RELAY (EFI MAIN RELAY) - BODY GROUND)

  1. Remove the No. 2 integration relay (EFI MAIN relay) from the engine room relay block.

  1. Disconnect the No. 2 integration relay connector.

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

    Standard Resistance:

    Tester Connection Condition Specified Condition
    1B-3 - Body ground Always Below 1 ?
  NG  
REPAIR OR REPLACE HARNESS OR CONNECTOR
 
OK  
   
PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

7.INSPECT NO. 2 INTEGRATION RELAY (IG2 RELAY)

  1. Inspect the No. 2 integration relay (IG2 relay) .

  NG  
REPLACE NO. 2 INTEGRATION RELAY (IG2 RELAY)
 
OK  
   

8.CHECK HARNESS AND CONNECTOR (NO. 2 INTEGRATION RELAY (IG2 RELAY) - ECM)

  1. Disconnect the ECM connector.

  1. Remove the No. 2 integration relay (IG2 relay) from the engine room relay block.

  1. Disconnect the No. 2 integration relay connector.

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

    Standard Resistance:

    Tester Connection Condition Specified Condition
    1A-4 - A60-28 (IGSW) Always Below 1 ?
    1A-4 or A60-28 (IGSW) - Body ground Always 10 k? or higher
  NG  
REPAIR OR REPLACE HARNESS OR CONNECTOR
 
OK  
   

9.CHECK HARNESS AND CONNECTOR (NO. 2 INTEGRATION RELAY (IG2 RELAY) - AUXILIARY BATTERY)

  1. Remove the No. 2 integration relay (IG2 relay) from the engine room relay block.

  1. Disconnect the No. 2 integration relay connector.

  1. Disconnect the negative (-) auxiliary battery terminal.

  1. Disconnect the positive (+) auxiliary battery terminal.

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

    Standard Resistance:

    Tester Connection Condition Specified Condition
    1C-1 - Positive (+) auxiliary battery terminal Always Below 1 ?
    1C-1 or Positive (+) auxiliary battery terminal - Body ground Always 10 k? or higher
  NG  
REPAIR OR REPLACE HARNESS OR CONNECTOR
 
OK  
   

10.CHECK HARNESS AND CONNECTOR (NO. 2 INTEGRATION RELAY (IG2 RELAY) - BODY GROUND)

  1. Remove the No. 2 integration relay (IG2 relay) from the engine room relay block.

  1. Disconnect the No. 2 integration relay connector.

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

    Standard Resistance:

    Tester Connection Condition Specified Condition
    1A-3 - Body ground Always Below 1 ?
  NG  
REPAIR OR REPLACE HARNESS OR CONNECTOR
 
OK  
   

11.CHECK HARNESS AND CONNECTOR (POWER MANAGEMENT CONTROL ECU - INTEGRATION RELAY (IG2 RELAY))

  1. Remove the No. 2 integration relay (IG2 relay) from the engine room relay block.

  1. Disconnect the No. 2 integration relay connector.

  1. Disconnect the power management control ECU connector.

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

    Standard Resistance:

    Tester Connection Condition Specified Condition
    A20-2 (IG2D) - 1A-2 Always Below 1 ?
  NG  
REPAIR OR REPLACE HARNESS OR CONNECTOR
 
OK  
   
CHECK ENTRY AND START SYSTEM (FOR START FUNCTION)