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ECM Power Source Circuit: Procedure

  1. INSPECT NO. 1 INTEGRATION RELAY (NO. 1 INTEGRATION RELAY - BODY GROUND) 
    1. Remove the No. 1 integration relay from the engine room relay block.
      Fig 1: Identifying No. 1 Integration Relay Connector Terminal
      GTY215357Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      1E-1 - Body ground Always 11 to 14 V
      TEXT IN ILLUSTRATION

      *1 Engine Room Relay Block
      *a Front view of wire harness connector
      (to No. 1 Integration Relay)
    3. Reinstall the No. 1 integration relay.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR (NO. 1 INTEGRATION RELAY - BATTERY) 

    OK: Go to next step 

  2. INSPECT NO. 1 INTEGRATION RELAY (EFI MAIN) 
    1. Inspect the No. 1 integration relay (EFI MAIN). Refer to ON-VEHICLE INSPECTION - Step 2 .

    NG → REPLACE NO. 1 INTEGRATION RELAY 

    OK: Go to next step 

  3. CHECK HARNESS AND CONNECTOR (+B, +B2 AND MREL CIRCUIT) 
    1. Check the harness and connectors between the No. 1 integration relay and ECM.
      1. Remove the No. 1 integration relay from the engine room relay block.
      2. Disconnect the ECM connector.
      3. Measure the resistance according to the value(s) in the table below.

        Standard Resistance (Check for Open)

        Tester Connection Condition Specified Condition
        F51-9 (MREL) - 1D-2 Always Below 1 Ω
        F51-22 (+B) - 1D-4 Always
        F51-23 (+B2) - 1D-4 Always

        Standard Resistance (Check for Short)

        Tester Connection Condition Specified Condition
        F51-9 (MREL) or 1D-2 - Body ground Always 10 kΩ or higher
        F51-22 (+B) or 1D-4 - Body ground Always
        F51-23 (+B2) or 1D-4 - Body ground Always
    2. Check the harness and connectors between the No. 1 integration relay and body ground.
      1. Measure the resistance according to the value(s) in the table below.

        Standard Resistance (Check for Open)

        Tester Connection Condition Specified Condition
        1D-3 - Body ground Always Below 1 Ω
    3. Reinstall the No. 1 integration relay.
    4. Reconnect the ECM connector.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  4. CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND) 
    1. Disconnect the ECM connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance (Check for Open)

      Tester Connection Condition Specified Condition
      B38-12 (E1) - Body ground Always Below 1 Ω
    3. Reconnect the ECM connector.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  5. INSPECT ECM (IGSW VOLTAGE) 
    1. Disconnect the ECM connectors.
      Fig 2: ECM Connectors Terminals Identification
      GTY230749Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Turn the ignition switch to ON.
    3. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      F50-21 (IGSW) - B38-12 (E1) Ignition switch ON 11 to 14 V
      TEXT IN ILLUSTRATION

      *a Rear view of wire harness connector
      (to ECM)
    4. Reconnect the ECM connectors.

    NG → See step   6 

    OK → See step   11 

  6. INSPECT NO. 1 INTEGRATION RELAY (IG2) 
    1. Inspect the No. 1 integration relay (IG2). Refer to ON-VEHICLE INSPECTION - Step 1 .

    NG → REPLACE NO. 1 INTEGRATION RELAY (IG2) 

    OK: Go to next step 

  7. CHECK HARNESS AND CONNECTOR (NO. 1 INTEGRATION RELAY (IG2) - ECM) 
    1. Remove the No. 1 integration relay (IG2) from the engine room relay block.
    2. Disconnect the ECM connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance (Check for Open)

      Tester Connection Condition Specified Condition
      1C-4 - F50-21 (IGSW) Always Below 1 Ω

      Standard Resistance (Check for Short)

      Tester Connection Condition Specified Condition
      1C-4 or F50-21 (IGSW) - Body ground Always 10 kΩ or higher
    4. Reinstall the No. 1 integration relay (IG2).
    5. Reconnect the ECM connector.
      RESULT

      Result Proceed to
      Out of normal range A
      Within normal range (w/ Smart Key System) B
      Within normal range (w/o Smart Key System) C

    B → See step   8 

    C → See step   9 

    A → REPAIR OR REPLACE HARNESS OR CONNECTOR 

  8. CHECK HARNESS AND CONNECTOR (NO. 1 INTEGRATION RELAY (IG2) - POWER MANAGEMENT CONTROL ECU) 
    1. Remove the No. 1 integration relay (IG2) from the engine room relay block.
    2. Disconnect the power management control ECU connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance (Check for Open)

      Tester Connection Condition Specified Condition
      1C-1 - F81-8 (IG2D) Always Below 1 Ω
      1C-3 - Body ground Always Below 1 Ω

      Standard Resistance (Check for Short)

      Tester Connection Condition Specified Condition
      F81-8 (IG2D) - Body ground Always 10 kΩ or higher
    4. Reinstall the No. 1 integration relay (IG2).
    5. Reconnect the power management control ECU connector.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK → CHECK SMART KEY SYSTEM 

  9. CHECK HARNESS AND CONNECTOR (NO. 1 INTEGRATION RELAY (IG2) - IGNITION SWITCH ASSEMBLY) 
    1. Remove the No. 1 integration relay (IG2) from the engine room relay block.
    2. Disconnect the ignition switch connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance (Check for Open)

      Tester Connection Condition Specified Condition
      1C-1 - F15-6 (IG2) Always Below 1 Ω
      1C-3 - Body ground Always Below 1 Ω

      Standard Resistance (Check for Short)

      Tester Connection Condition Specified Condition
      F15-6 (IG2) - Body ground Always 10 kΩ or higher
    4. Reinstall the No. 1 integration relay (IG2).
    5. Reconnect the ignition switch connector.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  10. INSPECT IGNITION SWITCH 
    1. Inspect the ignition switch. Refer to INSPECTION - Step 1 .

    NG → See step   12 

    OK → REPAIR OR REPLACE HARNESS OR CONNECTOR (IGNITION SWITCH ASSEMBLY - BATTERY) 

  11. REPLACE ECM. Refer to  REMOVAL 
  12. REPLACE IGNITION SWITCH. Refer to  REMOVAL 
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