HYBRID CONTROL SYSTEM ECU Power Source Circuit

DESCRIPTION

If the ignition switch is on (IG), the hybrid vehicle control ECU applies current to the MREL terminal to turn the IGCT relay on. This supplies power to the +B1 and +B2 terminals.

WIRING DIAGRAM

A004E51E09

PROCEDURE


  1. CHECK HYBRID VEHICLE CONTROL ECU (+B1, +B2 VOLTAGE)


    1. Turn the ignition switch to ON (IG).

    2. A004G8ZE02
      Text in Illustration
      *a

      Component with harness connected

      (Hybrid Vehicle Control ECU)

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A27-4 (+B1) - Body ground Ignition switch ON (IG) 11 to 14 V
      A26-1 (+B2) - Body ground Ignition switch ON (IG) 11 to 14 V

    3. Turn the ignition switch off.


    NG

    CHECK HYBRID VEHICLE CONTROL ECU (MREL VOLTAGE) Click here

    OK

  2. CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - BODY GROUND)


    1. Disconnect the hybrid vehicle control ECU connectors.

    2. A004FAME01
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to Hybrid Vehicle Control ECU)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      F55-5 (E01) - Body ground Always Below 1 Ω
      F55-6 (E1) - Body ground Always Below 1 Ω
      F56-5 (E02) - Body ground Always Below 1 Ω

    3. Connect the hybrid vehicle control ECU connectors.


    OK

    GO TO PROBLEM SYMPTOMS TABLE Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  3. CHECK HYBRID VEHICLE CONTROL ECU (MREL VOLTAGE)


    1. Turn the ignition switch to ON (IG).

    2. A004G0TE01
      Text in Illustration
      *a

      Component with harness connected

      (Hybrid Vehicle Control ECU)

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A27-6 (MREL) - Body ground Ignition switch ON (IG) 11 to 14 V

    NG

    REPLACE HYBRID VEHICLE CONTROL ECU Click here

    OK

  4. CHECK FUSE (IGCT NO. 2)


    1. A004FFYE01
      Text in Illustration
      *1 No. 2 Engine Room Relay Block
      *2 IGCT NO. 2 Fuse

      Remove the IGCT NO. 2 fuse from the No. 2 engine room relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      IGCT NO. 2 fuse terminals Always Below 1 Ω

    3. Install the IGCT NO. 2 fuse.


    NG

    CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - NO. 2 ENGINE ROOM RELAY BLOCK) Click here

    OK

  5. CHECK FUSE (IGCT-MAIN)


    1. A004F2NE01
      Text in Illustration
      *1 No. 2 Engine Room Relay Block
      *2 IGCT-MAIN Fuse

      Remove the IGCT-MAIN fuse from the No. 2 engine room relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      IGCT-MAIN fuse terminals Always Below 1 Ω

    3. Install the IGCT-MAIN fuse.


    NG

    CHECK HARNESS AND CONNECTOR (NO. 2 ENGINE ROOM RELAY BLOCK) Click here

    OK

  6. INSPECT RELAY (IGCT)


    1. Remove the IGCT relay from the No. 2 engine room relay block.

    2. A004F7ZE01
      Text in Illustration
      *1 IGCT Relay

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      3 - 5 Auxiliary battery voltage is not applied between terminals 1 and 2 10 kΩ or higher
      Auxiliary battery voltage is applied between terminals 1 and 2 Below 1 Ω

    3. Install the IGCT relay.


    NG

    REPLACE RELAY (IGCT)

    OK

  7. CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - NO. 2 ENGINE ROOM RELAY BLOCK)


    1. Remove the IGCT relay from the No. 2 engine room relay block.

    2. Disconnect the hybrid vehicle control ECU connectors.

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

      A004EY5E02
      Text in Illustration
      *1 No. 2 Engine Room Relay Block *2 IGCT Relay Holder
      *a

      Rear view of wire harness connector

      (to Hybrid Vehicle Control ECU)

      		 - -
      Standard Resistance
      Tester Connection Condition Specified Condition
      A27-4 (+B1) - 5 (IGCT relay holder) Always Below 1 Ω
      A26-1(+B2) - 5 (IGCT relay holder) Always Below 1 Ω

    4. Install the IGCT relay.

    5. Connect the hybrid vehicle control ECU connectors.


    NG

    REPLACE FUSE (IGCT-MAIN)

    OK

  8. CHECK HARNESS AND CONNECTOR (NO. 2 ENGINE ROOM RELAY BLOCK)


    1. Remove the IGCT MAIN fuse from the No. 2 engine room relay block.

    2. Remove the IGCT relay from the No. 2 engine room relay block.

    3. A004G7QE01
      Text in Illustration
      *1 No. 2 Engine Room Relay Block
      *2 IGCT Relay Holder
      *3 IGCT-MAIN Fuse Holder

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      3 (IGCT relay holder) - 2 (IGCT-MAIN fuse holder) Always Below 1 Ω

    4. Install the IGCT MAIN fuse.

    5. Install the IGCT relay.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  9. CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - NO. 2 ENGINE ROOM RELAY BLOCK)


    1. Remove the IGCT relay from the No. 2 engine room relay block.

    2. Disconnect the hybrid vehicle control ECU connector.

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

      A004EKME01
      Text in Illustration
      *1 No. 2 Engine Room Relay Block *2 IGCT Relay Holder
      *a

      Rear view of wire harness connector

      (to Hybrid Vehicle Control ECU)

      		 - -
      Standard Resistance
      Tester Connection Condition Specified Condition
      A27-6 (MREL) - 1 (IGCT relay holder) Always Below 1 Ω
      A27-6 (MREL) or 1 (IGCT relay holder) - Body ground and other terminals Always 10 kΩ or higher

    4. Install the IGCT relay.

    5. Connect the hybrid vehicle control ECU connectors.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  10. CHECK HARNESS AND CONNECTOR (NO. 2 ENGINE ROOM RELAY BLOCK - BODY GROUND)


    1. Remove the IGCT relay from the No. 2 engine room relay block.

    2. A004G49E01
      Text in Illustration
      *1 No. 2 Engine Room Relay Block
      *2 IGCT Relay Holder

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      2 (IGCT relay holder) - Body ground Always Below 1 Ω

    3. Install the IGCT relay.


    OK

    CHECK FOR INTERMITTENT PROBLEMS Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  11. CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - NO. 2 ENGINE ROOM RELAY BLOCK)


    1. Disconnect the shift lever position sensor connector.

    2. Remove the IGCT NO. 2 fuse from the No. 2 engine room relay block.

    3. Disconnect the hybrid vehicle control ECU connector.

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

      A004GB8E02
      Text in Illustration
      *1 No. 2 Engine Room Relay Block *2 IGCT NO. 2 Fuse Holder
      *a

      Rear view of wire harness connector

      (to Hybrid Vehicle Control ECU)

      		 - -
      Standard Resistance
      Tester Connection Condition Specified Condition
      A27-4 (+B1) or 2 (IGCT NO. 2 fuse holder) - Body ground and other terminals Always 10 kΩ or higher
      A26-1 (+B2) or 2 (IGCT NO. 2 fuse holder) - Body ground and other terminals Always 10 kΩ or higher

    5. Install the IGCT NO. 2 fuse.

    6. Connect the shift lever position sensor connector.

    7. Connect the hybrid vehicle control ECU connectors.


    OK

    REPLACE FUSE (IGCT NO. 2)

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR Click here

  12. CHECK HARNESS AND CONNECTOR (NO. 2 ENGINE ROOM RELAY BLOCK)


    1. A004FZFE01
      Text in Illustration
      *1 No. 2 Engine Room Relay Block
      *2 IGCT-MAIN Fuse
      *3 IGCT NO. 2 Fuse
      *4 PCU Fuse
      *5 IGCT NO. 3 Fuse

      Remove the IGCT-MAIN fuse, IGCT NO. 2 fuse, IGCT NO. 3 fuse and PCU fuse from the No. 2 engine room relay block.

    2. Remove the IGCT relay from the No. 2 engine room relay block.

    3. A004G7QE01
      Text in Illustration
      *1 No. 2 Engine Room Relay Block
      *2 IGCT Relay Holder
      *3 IGCT-MAIN Fuse Holder

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      3 (IGCT relay holder) or 2 (IGCT-MAIN fuse holder) - Body ground and other terminals Always 10 kΩ or higher
    4. A004G96E01
      Text in Illustration
      *1 No. 2 Engine Room Relay Block
      *2 IGCT Relay Holder
      *3 IGCT NO. 2 Fuse Holder

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      5 (IGCT relay holder) or 2 (IGCT NO. 2 fuse holder) - Body ground and other terminals Always 10 kΩ or higher

    5. Install the IGCT-MAIN fuse, IGCT NO. 2 fuse, IGCT NO. 3 fuse and PCU fuse.

    6. Install the IGCT relay.


    OK

    CHECK FOR INTERMITTENT PROBLEMS Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR Click here

  13. REPAIR OR REPLACE HARNESS OR CONNECTOR


    NEXT

    REPLACE FUSE (IGCT NO. 2)

  14. REPAIR OR REPLACE HARNESS OR CONNECTOR


    NEXT

    REPLACE FUSE (IGCT-MAIN)