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ECU Power Source Circuit [11/2021 - ]: Procedure

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  1. CHECK HYBRID VEHICLE CONTROL ECU (+B1, +B2 VOLTAGE) 
    1. Turn the ignition switch to ON.
    2. Measure the voltage according to the value(s) in the table below.
      GTY1079009Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Hybrid Vehicle Control ECU)      		 - -

      Standard Voltage

      Tester Connection Condition Specified Condition
      D67-7 (+B1) - Body ground Ignition switch ON 11 to 14 V
      D67-8 (+B2) - Body ground Ignition switch ON 11 to 14 V
    3. Turn the ignition switch off.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  3

    Result: 

    OK 

    See step  2

  2. CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - BODY GROUND) 
    1. Disconnect the hybrid vehicle control ECU connectors.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      A27-10 (E01) - Body ground Always Below 1 Ω
      D67-1 (E12) - Body ground Always Below 1 Ω
      D67-15 (E1) - Body ground Always Below 1 Ω
    3. Reconnect the hybrid vehicle control ECU connectors.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    GO TO PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [11/2021 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  3. CHECK HYBRID VEHICLE CONTROL ECU (MREL TERMINAL VOLTAGE) 
    1. Turn the ignition switch to ON.
    2. Measure the voltage according to the value(s) in the table below.
      GTY1078467Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Hybrid Vehicle Control ECU)      		 - -

      Standard Voltage

      Tester Connection Condition Specified Condition
      D67-47 (MREL) - Body ground Ignition switch ON 11 to 14 V
    3. Turn the Ignition switch off.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE HYBRID VEHICLE CONTROL ECU. Refer to  REMOVAL [11/2021 - ] 

    Result: 

    OK 

    See step  4

  4. CHECK FUSE (PM-IGCT) 
    1. Remove the PM-IGCT fuse from the No. 1 engine room relay block and No. 1 junction block assembly.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      PM-IGCT fuse Always Below 1 Ω
    3. Install the PM-IGCT fuse.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  11

    Result: 

    OK 

    See step  5

  5. CHECK FUSE (IGCT) 
    1. Remove the IGCT fuse from the No. 1 engine room relay block and No. 1 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 Always Below 1 Ω
    3. Install the IGCT fuse.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  12

    Result: 

    OK 

    See step  6

  6. INSPECT RELAY (IGCT) 
    1. Remove the IGCT relay from the No. 1 engine room relay block and No. 1 junction block assembly.
    2. Measure the resistance according to the value(s) in the table below.
      GTY434306Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 IGCT Relay

      Standard Resistance

      Tester Connection Condition Specified Condition
      3 - 5 Auxiliary battery voltage not applied between terminals 1 and 2 10 kΩ or higher
      Auxiliary battery voltage applied between terminals 1 and 2 Below 1 Ω
    3. Install the IGCT relay.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE RELAY (IGCT) 

    Result: 

    OK 

    See step  7

  7. CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - NO. 1 ENGINE ROOM RELAY BLOCK AND NO. 1 JUNCTION BLOCK ASSEMBLY) 
    1. Disconnect the hybrid vehicle control ECU connector.
    2. Remove the PM-IGCT fuse from the No. 1 engine room relay block and No. 1 junction block assembly.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      D67-7 (+B1) - 2 (PM-IGCT fuse holder) Always Below 1 Ω
      D67-8 (+B2) - 2 (PM-IGCT fuse holder) Always Below 1 Ω
    4. Install the PM-IGCT fuse.
    5. Reconnect the hybrid vehicle control ECU connector.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  8

  8. CHECK HARNESS AND CONNECTOR (NO. 1 ENGINE ROOM RELAY BLOCK AND NO. 1 JUNCTION BLOCK ASSEMBLY) 
    1. Remove the IGCT fuse, PM-IGCT fuse and IGCT relay from the No. 1 engine room relay block and No. 1 junction block assembly.
    2. 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 fuse holder) Always Below 1 Ω
      5 (IGCT relay holder) - 1 (PM-IGCT fuse holder) Always Below 1 Ω
    3. Install the IGCT fuse, PM-IGCT fuse and IGCT relay.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  9

  9. CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - NO. 1 ENGINE ROOM RELAY BLOCK AND NO. 1 JUNCTION BLOCK ASSEMBLY) 
    1. Disconnect the hybrid vehicle control ECU connector.
    2. Remove the IGCT relay from the No. 1 engine room relay block and No. 1 junction block assembly.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      D67-47 (MREL) - 1 (IGCT relay holder) Always Below 1 Ω
      D67-47 (MREL) or 1 (IGCT relay holder) - Body ground and other terminals Always 10 kΩ or higher
    4. Install the IGCT relay.
    5. Reconnect the hybrid vehicle control ECU connector.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  10

  10. CHECK HARNESS AND CONNECTOR (NO. 1 ENGINE ROOM RELAY BLOCK AND NO. 1 JUNCTION BLOCK ASSEMBLY - BODY GROUND) 
    1. Remove the IGCT relay from the No. 1 engine room relay block and No. 1 junction block assembly.
    2. 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.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    CHECK FOR INTERMITTENT PROBLEMS. Refer to  CHECK FOR INTERMITTENT PROBLEMS [11/2021 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  11. CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU - NO. 1 ENGINE ROOM RELAY BLOCK AND NO. 1 JUNCTION BLOCK ASSEMBLY) 
    1. Remove the PM-IGCT fuse from the No. 1 engine room relay block and No. 1 junction block assembly.
    2. Disconnect the hybrid vehicle control ECU connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      D67-7 (+B1) or 2 (PM-IGCT fuse holder) - Body ground and other terminals Always 10 kΩ or higher
      D67-8 (+B2) or 2 (PM-IGCT fuse holder) - Body ground and other terminals Always 10 kΩ or higher
    4. Reconnect the hybrid vehicle control ECU connector.
    5. Install the PM-IGCT fuse.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE FUSE (IGCT SCENE) 

    Result: 

    NG 

    See step  13

  12. CHECK HARNESS AND CONNECTOR (NO. 1 ENGINE ROOM RELAY BLOCK AND NO. 1 JUNCTION BLOCK ASSEMBLY) 
    1. Remove the IGCT fuse, IGCT NO. 1 fuse and IGCT relay from the No. 1 engine room relay block and No. 1 junction block assembly.
    2. 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 fuse holder) - Body ground and other terminals Always 10 kΩ or higher
      5 (IGCT relay holder) or 1 (IGCT NO. 1 fuse holder) - Body ground and other terminals Always 10 kΩ or higher
    3. Install the IGCT fuse, IGCT NO. 1 fuse and IGCT relay.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE FUSE (IGCT) 

    Result: 

    NG 

    See step  14

  13. REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    REPLACE FUSE (IGCT NO. 1) 

  14. REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    REPLACE FUSE (IGCT) 

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