HYBRID CONTROL SYSTEM ECU Power Source Circuit

DESCRIPTION

When the power switch is turned on (IG), current flows from the MREL terminal of the hybrid vehicle control ECU to the IGCT relay. This closes the IGCT relay contact points and supplies power to the +B1 and +B2 terminals of the hybrid vehicle control ECU.

WIRING DIAGRAM

B005XLXE09

PROCEDURE


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


    1. Turn the power switch on (IG).

    2. B005YKWE02
      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 Condition Specified Condition
      A22-4 (+B1) - Body ground Power switch on (IG) 11 to 14 V
      A21-1 (+B2) - Body ground Power switch on (IG) 11 to 14 V

    3. Turn the power 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 L5 and L6 hybrid vehicle control ECU connectors.

    2. B005YALE03
      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
      L5-5 (E01) - Body ground Always Below 1 Ω
      L5-6 (E1) - Body ground Always Below 1 Ω
      L6-4 (E12) - Body ground Always Below 1 Ω
      L6-5 (E02) - Body ground Always Below 1 Ω

    3. Reconnect the L5 and L6 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 power switch on (IG).

    2. B005Z0PE03
      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 Condition Specified Condition
      A22-6 (MREL) - Body ground Power switch on (IG) 11 to 14 V

    3. Turn the power switch off.


    NG

    REPLACE HYBRID VEHICLE CONTROL ECU Click here

    OK

  4. CHECK FUSE (IGCT NO. 2)


    1. Remove the IGCT NO. 2 fuse from the engine room relay block and junction block assembly.

    2. B005Y2EE05
      Text in Illustration
      *1 Engine Room Relay Block and Junction Block Assembly
      *2 IGCT NO. 2 Fuse

      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 - ENGINE ROOM RELAY BLOCK AND JUNCTION BLOCK ASSEMBLY) Click here

    OK

  5. CHECK FUSE (IGCT)


    1. B005YH5E05
      Text in Illustration
      *1 Engine Room Relay Block and Junction Block Assembly
      *2 IGCT Fuse

      Remove the IGCT fuse from the engine room relay block and junction block assembly.

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

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

    3. Install the IGCT fuse.


    NG

    CHECK HARNESS AND CONNECTOR (ENGINE ROOM RELAY BLOCK AND JUNCTION BLOCK ASSEMBLY (IGCT FUSE - IGCT NO. 2 FUSE)) Click here

    OK

  6. INSPECT RELAY (IGCT)


    1. Remove the IGCT relay from the engine room relay block and junction block assembly.

    2. B005Z48E01
      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 - ENGINE ROOM RELAY BLOCK AND JUNCTION BLOCK ASSEMBLY)


    1. Remove the IGCT relay from the engine room relay block and junction block assembly.

    2. Disconnect the A21 and A22 hybrid vehicle control ECU connectors.

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

      B005YCKE02
      Text in Illustration
      *1 Engine Room Relay Block and Junction Block Assembly *2 IGCT relay
      *a

      Rear view of wire harness connector

      (to Hybrid Vehicle Control ECU)

      		 - -
      Standard Resistance
      Tester Connection Condition Specified Condition
      A22-4 (+B1) - 5 (IGCT relay) Always Below 1 Ω
      A21-1 (+B2) - 5 (IGCT relay) Always Below 1 Ω

    4. Install the IGCT relay.

    5. Reconnect the A21 and A22 hybrid vehicle control ECU connectors.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  8. CHECK HARNESS AND CONNECTOR (ENGINE ROOM RELAY BLOCK AND JUNCTION BLOCK ASSEMBLY (IGCT RELAY - IGCT FUSE))


    1. B005YNGE05
      Text in Illustration
      *1 Engine Room Relay Block and Junction Block Assembly
      *2 IGCT Fuse

      Remove the IGCT fuse from the engine room relay block and junction block assembly.

    2. Remove the IGCT relay from the engine room relay block and junction block assembly.

    3. B005XYBE03
      Text in Illustration
      *1 Engine Room Relay Block and Junction Block Assembly
      *2 IGCT Fuse
      *3 IGCT Relay

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

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

    4. Install the IGCT fuse.

    5. Install the IGCT relay.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  9. CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - ENGINE ROOM RELAY BLOCK AND JUNCTION BLOCK ASSEMBLY)


    1. Remove the IGCT relay from the engine room relay block and junction block assembly.

    2. Disconnect the A22 hybrid vehicle control ECU connector.

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

      B005Y0UE01
      Text in Illustration
      *1 Engine Room Relay Block and Junction Block Assembly *2 IGCT Relay
      *a

      Rear view of wire harness connector

      (to Hybrid Vehicle Control ECU)

      		 - -
      Standard Resistance
      Tester Connection Condition Specified Condition
      A22-6 (MREL) - 1 (IGCT relay) Always Below 1 Ω
      A22-6 (MREL) or 1 (IGCT relay) - Body ground and other terminals Always 10 kΩ or higher

    4. Install the IGCT relay.

    5. Reconnect the A22 hybrid vehicle control ECU connectors.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  10. CHECK HARNESS AND CONNECTOR (ENGINE ROOM RELAY BLOCK AND JUNCTION BLOCK ASSEMBLY - BODY GROUND)


    1. Remove the IGCT relay from the engine room relay block and junction block assembly.

    2. B005ZIYE02
      Text in Illustration
      *1 Engine Room Relay Block and Junction Block Assembly
      *2 IGCT Relay

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      2 (IGCT relay) - 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 - ENGINE ROOM RELAY BLOCK AND JUNCTION BLOCK ASSEMBLY)

    CAUTION:

    Be sure to wear insulated gloves.


    1. Check that the service plug grip is not installed.

      Note

      After removing the service plug grip, do not turn the power switch on (READY), unless instructed by the repair manual because this may cause a malfunction.

    2. Disconnect the A59 inverter with converter assembly connector.

    3. Disconnect the A23 transmission control ECU assembly connector.

    4. Remove the No. 1 hybrid vehicle battery carrier bracket sub-assembly Click here.

    5. Disconnect the L144 battery smart unit connector.

    6. B005XDTE05
      Text in Illustration
      *1 Engine Room Relay Block and Junction Block Assembly
      *2 IGCT No. 2 Fuse

      Remove the IGCT No. 2 fuse from the engine room relay block and junction block assembly.

    7. Disconnect the A21 and A22 hybrid vehicle control ECU connectors.

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

      B005ZRFE02
      Text in Illustration
      *1 Engine Room Relay Block and Junction Block Assembly *2 IGCT No. 2 Fuse
      *a

      Rear view of wire harness connector

      (to Hybrid Vehicle Control ECU)

      		 - -
      Standard Resistance
      Tester Connection Condition Specified Condition
      A22-4 (+B1) or 2 (IGCT No. 2 fuse) - Body ground and other terminals Always 10 kΩ or higher
      A21-1 (+B2) or 2 (IGCT No. 2 fuse) - Body ground and other terminals Always 10 kΩ or higher

    9. Install the IGCT No. 2 fuse.

    10. Reconnect the A21 and A22 hybrid vehicle control ECU connectors.

    11. Reconnect the L144 battery smart unit connector.

    12. Install the No. 1 hybrid vehicle battery carrier bracket sub-assembly.

    13. Reconnect the A23 transmission control ECU assembly connector.

    14. Reconnect the A59 inverter with converter assembly connector.


    OK

    REPLACE FUSE (IGCT NO. 2)

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR Click here

  12. CHECK HARNESS AND CONNECTOR (ENGINE ROOM RELAY BLOCK AND JUNCTION BLOCK ASSEMBLY (IGCT FUSE - IGCT NO. 2 FUSE))


    1. B005ZI1E04
      Text in Illustration
      *1 Engine Room Relay Block and Junction Block Assembly
      *2 IGCT Fuse
      *3 IGCT No. 3 fuse
      *4 IGCT No. 2 fuse
      *5 PCU Fuse

      Remove the IGCT fuse, IGCT No. 2 fuse, IGCT No. 3 fuse and PCU fuse from the engine room relay block and junction block assembly.

    2. Remove the IGCT relay from the engine room relay block and junction block assembly.

    3. B005XYBE04
      Text in Illustration
      *1 Engine Room Relay Block and Junction Block Assembly
      *2 IGCT Fuse
      *3 IGCT Relay

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      3 (IGCT relay) or 2 (IGCT fuse) - Body ground and other terminals Always 10 kΩ or higher
    4. B005YTLE02
      Text in Illustration
      *1 Engine Room Relay Block and Junction Block Assembly
      *2 IGCT No. 2 Fuse
      *3 IGCT Relay

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      5 (IGCT relay) or 1 (IGCT No. 2 fuse) - Body ground and other terminals Always 10 kΩ or higher

    5. Install the IGCT fuse, IGCT No. 2 fuse, IGCT No. 3 fuse and PCU fuse.

    6. Install the IGCT relay.


    OK

    REPLACE FUSE (IGCT)

    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)