2007 Toyota Yaris S, AutomaticFACTORY OEM SERVICE PROCEDURE

Inspection Procedure

  1. INSPECT INTEGRATION RELAY (INTEGRATION RELAY - BODY GROUND) 
    1. Remove the integration relay from the engine room relay block.
    2. Measure the voltage between the terminal of the integration relay and body ground.

      Standard voltage 

      VOLTAGE SPECIFICATION

      Tester Connections Specified Conditions
      Engine room relay block (1C-1) - Body ground 11 to 14 V
    3. Reinstall the integration relay.

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Fig 1: Identifying Integration Relay Terminals
    G04828325Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: GO TO NEXT STEP 

  2. INSPECT INTEGRATION RELAY (EFI RELAY AND IG2 RELAY) 
    1. Remove the integration relay from the engine room relay block.
    2. Inspect the EFI fuse and the AM2 fuse.
      1. Remove the EFI fuse and AM2 fuse from the integration relay.
      2. Check the resistance of the EFI fuse and AM2 fuse.

        Standard resistance: 

        Below 1 Ω 

      3. Reinstall the EFI fuse and the AM2 fuse.
    3. Inspect the EFI relay and the IG2 relay.
      1. Check the resistance between the terminals shown below.

        Standard resistance 

        RESISTANCE SPECIFICATION

        Tester Connections Specified Conditions
        1C-1 - 1A-4 10 kΩ or higher
        Below 1 Ω (when battery voltage is applied to terminals 1A-2 and 1A-3)
        1C-1 - 1B-4 10 kΩ or higher
        Below 1 Ω (when battery voltage is applied to terminals 1A-2 and 1A-3)
        1C-1 - 1B-1 Below 1 Ω
        Fig 2: Identifying EFI & AM2 Fuse
        G04828326Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      2. Reinstall the integration relay.

    NG: REPLACE INTEGRATION RELAY 

    OK: GO TO NEXT STEP 

  3. CHECK HARNESS AND CONNECTOR (+B, +B2 AND MREL CIRCUIT) 
    1. Check the harness and the connectors between the integration relay and the ECM.
      1. Remove the integration relay from the engine room relay block.
      2. Disconnect the A21 ECM connector.
      3. Check the resistance.

        Standard resistance (Check for open) 

        RESISTANCE SPECIFICATION

        Tester Connections Specified Conditions
        MREL (A21-44) - Engine room relay block (1A-2) Below 1 Ω
        +B (A21-2) - Engine room relay block (1A-4)
        +B2 (A21-1) - Engine room relay block (1A-4)

        Standard resistance (Check for short) 

        RESISTANCE SPECIFICATION

        Tester Connections Specified Conditions
        MREL (A21-44) - Engine room relay block (1A-2) - Body ground Below 10 kΩ or higher
        +B (A21-2) - Engine room relay block (1A-4) - Body ground
        +B2 (A21-1) - Engine room relay block (1A-4) - Body ground
    2. Check the harness and the connectors between the integration relay and body ground.
      1. Check the resistance.

        Standard resistance (Check for open) 

        RESISTANCE SPECIFICATION

        Tester Connections Specified Conditions
        Engine room relay block (1A-3) - Body ground Below 1 Ω
    3. Reinstall the integration relay.
    4. Reconnect the ECM connector.
      Fig 3: Identifying Integration Relay & ECM Connectors
      G04828327Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: GO TO NEXT STEP 

  4. CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND) 
    1. Disconnect the C20 ECM connector.
    2. Check the resistance.

      Standard resistance (Check for open) 

      RESISTANCE SPECIFICATION

      Tester Connections Specified Conditions
      E1 (C20-104) - Body ground Below 1 Ω
    3. Reconnect the ECM connector.

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: GO TO NEXT STEP 

    Fig 4: Identifying C20 ECM Connectors
    G04828328Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  5. INSPECT ECM (IGSW VOLTAGE) 
    1. Disconnect the C20 and A21 ECM connectors.
    2. Turn the ignition switch to ON.
    3. Measure the voltage between the terminals of the C20 and A21 ECM connectors.

      Standard voltage 

      VOLTAGE SPECIFICATION

      Tester Connections Specified Conditions
      IGSW (A21-28) - E1 (C20-104) 11 to 14 V
    4. Reconnect the ECM connectors.

    OK: REPLACE ECM 

    Fig 5: Identifying C20 & A21 ECM Connectors
    G04828329Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: GO TO NEXT STEP 

  6. INSPECT FUSE (IGN FUSE) 
    1. Remove the IGN fuse from the main body ECU.
    2. Check the IGN fuse resistance.

      Standard resistance: Below 1 Ω 

    3. Reinstall the IGN fuse.

    NG: CHECK FOR SHORTS IN ALL HARNESSES AND CONNECTORS CONNECTED TO FUSE AND REPLACE FUSE 

    Fig 6: Identifying IGN Fuse
    G04828330Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: GO TO NEXT STEP 

  7. CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY - ECM, INTEGRATION RELAY - BODY GROUND) 
    1. Remove the integration relay from the engine room relay block.
    2. Disconnect the A21 ECM connector.
    3. Check the resistance.

      Standard resistance (Check for open) 

      RESISTANCE SPECIFICATION

      Tester Connections Specified Conditions
      Engine room relay block (1B-4) - IGSW (A21-28) Below 1 Ω

      Standard resistance (Check for short) 

      RESISTANCE SPECIFICATION

      Tester Connections Specified Conditions
      Engine room relay block (1B-4) or IGSW (A21-28) - Body ground 10 kΩ or higher
    4. Reinstall the integration relay.
    5. Reconnect the ECM connector.

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Fig 7: Identifying A21 ECM Connector
    G04828331Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: GO TO NEXT STEP 

  8. CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY - IGNITION SWITCH ASSEMBLY) 
    1. Check the harness and the connectors between the integration relay and the ignition switch.
      1. Remove the integration relay from the engine room relay block.
      2. Disconnect the D8 ignition switch connector.
      3. Check the resistance.

        Standard resistance (Check for open) 

        RESISTANCE SPECIFICATION

        Tester Connections Specified Conditions
        Engine room relay block (1B-2) - IG2 (D8-6) Below 1 Ω

        Standard resistance (Check for short) 

        RESISTANCE SPECIFICATION

        Tester Connections Specified Conditions
        Engine room relay block (1B-2) or IG2 (D8-6) - Body ground 10 kΩ or higher
    2. Check the harness and the connectors between the integration relay and body ground.
      1. Check the resistance.

        Standard resistance (Check for open) 

        RESISTANCE SPECIFICATION

        Tester Connections Specified Conditions
        Engine room relay block (1B-3) - Body ground Below 1 Ω
    3. Reinstall the integration relay.
    4. Reconnect the ignition switch connector.

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Fig 8: Identifying Integration Relay & Ignition Switch Connectors
    G04828332Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: GO TO NEXT STEP 

  9. INSPECT IGNITION OR STARTER SWITCH ASSEMBLY 
    1. Disconnect the D8 ignition switch connector.
    2. Check the resistance between the terminals shown below.

      Standard resistance 

      RESISTANCE SPECIFICATION

      Key Positions Tester Connections Specified Conditions
      LOCK - 10 kΩ or higher
      ACC 2-4 Below 1 Ω
      ON 1-2-4
      5-6
      START 1-3-4
      5-6-7
    3. Reconnect the ignition switch connector.

    NG: REPLACE IGNITION OR STARTER SWITCH ASSEMBLY 

    Fig 9: Identifying D8 Ignition Switch Connector
    G04828333Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: REPAIR OR REPLACE HARNESS OR CONNECTOR 

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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