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Home >> Toyota >> 2021 >> Mirai XLE >> Repair and Diagnosis >> Hybrid/Electric Powertrain >> Testing and Diagnosis >> Hybrid Battery System - Diagnostic Codes (8 Of 8) & Symptom Tests >> Hybrid Battery System >> ECU Power Source Circuit [12/2023 - ] >> Procedure

ECU Power Source Circuit [12/2023 - ]: Procedure

  1. CHECK HARNESS AND CONNECTOR (IGCT VOLTAGE) 
    WARNING:

    Be sure to wear insulated gloves and protective goggles.

    1. Check that the service plug grip and FC converter power outlet cable are not installed.
      NOTE:

      After removing the service plug grip and FC converter power outlet cable, do not turn the ignition switch to ON (READY), unless instructed by the appropriate service information because this may cause a malfunction.

    2. Remove the center No. 2 floor to brace extension.

      HINT: 

      Refer to REMOVAL [12/2023 - ]

    3. Disconnect the G156 No. 2 EV battery pack wire connector.
      GTY972715Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      NOTE:

      Before disconnecting the connector, check that it is not loose or disconnected.

    4. Connect the cable to the negative (-) auxiliary battery terminal.
    5. Turn the ignition switch to ON.
    6. Measure the voltage according to the value(s) in the table below.
      GTY972477Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (No. 2 EV Battery Pack Wire Connector)

      Standard Voltage

      Tester Connection Condition Specified Condition
      G156-14 (IGCT) - Body ground Ignition switch ON 11 to 14 V
      NOTE:
      • Turning the ignition switch to ON with the service plug grip and FC converter power outlet cable removed causes other DTCs to be stored. Clear the DTCs after performing this inspection.
      • If the ignition switch is turned to ON with the connectors disconnected, other DTCs will be stored. Be sure to clear the DTCs after the inspection.
    7. Turn the ignition switch off.
    8. Disconnect the cable from the negative (-) auxiliary battery terminal.
    9. Reconnect the G156 No. 2 EV battery pack wire connector.
    10. Install the center No. 2 floor to brace extension.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  4

    Result: 

    OK 

    See step  2

  2. CHECK HARNESS AND CONNECTOR (NO. 2 EV BATTERY PACK WIRE CONNECTOR - BODY GROUND) 
    WARNING:

    Be sure to wear insulated gloves and protective goggles.

    1. Check that the service plug grip and FC converter power outlet cable are not installed.
      NOTE:

      After removing the service plug grip and FC converter power outlet cable, do not turn the ignition switch to ON (READY), unless instructed by the appropriate service information because this may cause a malfunction.

    2. Remove the center No. 2 floor to brace extension.

      Refer to REMOVAL [12/2023 - ]

    3. Disconnect the G156 No. 2 EV battery pack wire connector.
      GTY972715Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      NOTE:

      Before disconnecting the connector, check that it is not loose or disconnected.

    4. Measure the resistance according to the value(s) in the table below.
      GTY972475Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (No. 2 EV Battery Pack Wire Connector)

      Standard Resistance

      Tester Connection Condition Specified Condition
      G156-1 (GND) - Body ground Always Below 1 Ω
      G156-10 (GND1) - Body ground Always Below 1 Ω
    5. Reconnect the G156 No. 2 EV battery pack wire connector.
    6. Install the center No. 2 floor to brace extension.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  3

  3. CHECK HARNESS AND CONNECTOR (BATTERY ECU ASSEMBLY - NO. 2 EV BATTERY PACK WIRE CONNECTOR) 
    WARNING:

    Be sure to wear insulated gloves and protective goggles.

    1. Check that the service plug grip and FC converter power outlet cable are not installed.
      NOTE:

      After removing the service plug grip and FC converter power outlet cable, do not turn the ignition switch to ON (READY), unless instructed by the appropriate service information because this may cause a malfunction.

    2. Remove the upper No. 1 EV battery cover sub-assembly.

      Refer to REMOVAL [12/2023 - ]

    3. Disconnect the z26 battery ECU assembly connector.
      GTY972496Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      NOTE:
      • Before disconnecting the connector, check that it is not loose or disconnected.
      • Check the terminals of the connector for deformation and corrosion.
    4. Measure the resistance according to the value(s) in the tables below.
      GTY972443Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (No. 2 EV Battery Pack Wire Connector)
      *b Rear view of wire harness connector
      (to Battery ECU Assembly)

      Standard Resistance

      Tester Connection Condition Specified Condition
      z26-40 (IGCT) - G156-14 (IGCT) Always Below 1 Ω
      z26-11 (GND) - G156-1 (GND) Always Below 1 Ω
      z26-31 (GND1) - G156-10 (GND1) Always Below 1 Ω
      z26-40 (IGCT) or G156-14 (IGCT) - Body ground and other terminals Always 10 kΩ or higher
      z26-11 (GND) or G156-1 (GND) - Body ground and other terminals Always 10 kΩ or higher
      z26-31 (GND1) or G156-10 (GND1) - Body ground and other terminals Always 10 kΩ or higher
    5. Reconnect the z26 battery ECU assembly connector.
    6. Install the upper No. 1 EV battery cover sub-assembly.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    GO TO PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [12/2023 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  4. CHECK FUSE (IGCT NO. 6) 
    1. Remove the IGCT NO. 6 fuse from the luggage room relay block assembly.
      GTY1003966Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Luggage Room Relay Block Assembly
      *a IGCT NO. 6 Fuse
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      IGCT NO. 6 fuse terminals 1 - 2 Always Below 1 Ω
    3. Install the IGCT NO. 6 fuse to the luggage room relay block assembly.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  7

    Result: 

    OK 

    See step  5

  5. CHECK HARNESS AND CONNECTOR (NO. 2 EV BATTERY PACK WIRE CONNECTOR - LUGGAGE ROOM RELAY BLOCK ASSEMBLY) 
    WARNING:

    Be sure to wear insulated gloves and protective goggles.

    1. Check that the service plug grip and FC converter power outlet cable are not installed.
      NOTE:

      After removing the service plug grip and FC converter power outlet cable, do not turn the ignition switch to ON (READY), unless instructed by the appropriate service information because this may cause a malfunction.

    2. Remove the center No. 2 floor to brace extension.

      Refer to REMOVAL [12/2023 - ]

    3. Disconnect the G156 No. 2 EV battery pack wire connector.
      GTY972715Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      NOTE:

      Before disconnecting the connector, check that it is not loose or disconnected.

    4. Remove the IGCT NO. 6 fuse from the luggage room relay block assembly.
    5. Measure the resistance according to the value(s) in the table below.
      GTY1003311Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Luggage Room Relay Block Assembly - -
      *a IGCT NO. 6 Fuse Holder *b Front view of wire harness connector
      (No. 2 EV Battery Pack Wire Connector)

      Standard Resistance

      Tester Connection Condition Specified Condition
      G156-14 (IGCT) - 2 (IGCT NO. 6 fuse holder) Always Below 1 Ω
    6. Install the IGCT NO. 6 fuse to the luggage room relay block assembly.
    7. Reconnect the G156 No. 2 EV battery pack wire connector.
    8. Install the center No. 2 floor to brace extension.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  6

  6. CHECK HARNESS AND CONNECTOR (LUGGAGE ROOM RELAY BLOCK ASSEMBLY) 
    1. Remove the IGCT NO. 6 fuse from the luggage room relay block assembly.
    2. Remove the IGCT NO. 2 relay from the luggage room relay block assembly.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      5 (IGCT NO. 2 relay holder) - 1 (IGCT NO. 6 fuse holder) Always Below 1 Ω
      GTY1003846Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Luggage Room Relay Block Assembly
      *a IGCT NO. 6 Fuse Holder
      *b IGCT NO. 2 Relay Holder
    4. Install the IGCT NO. 2 relay from the luggage room relay block assembly.
    5. Install the IGCT NO. 6 fuse from the luggage room relay block assembly.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    CHECK ECU Power Source Circuit (HYBRID CONTROL SYSTEM). Refer to  ECU Power Source Circuit [12/2023 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  7. CHECK HARNESS AND CONNECTOR (NO. 2 EV BATTERY PACK WIRE CONNECTOR - LUGGAGE ROOM RELAY BLOCK ASSEMBLY) 
    WARNING:

    Be sure to wear insulated gloves and protective goggles.

    1. Check that the service plug grip and FC converter power outlet cable are not installed.
      NOTE:

      After removing the service plug grip and FC converter power outlet cable, do not turn the ignition switch to ON (READY), unless instructed by the appropriate service information because this may cause a malfunction.

    2. Remove the center No. 2 floor to brace extension.

      Refer to REMOVAL [12/2023 - ]

    3. Disconnect the G156 No. 2 EV battery pack wire connector.
      GTY972715Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      NOTE:

      Before disconnecting the connector, check that it is not loose or disconnected.

    4. Remove the IGCT NO. 6 fuse from the luggage room relay block assembly.
    5. Measure the resistance according to the value(s) in the table below.
      GTY1003311Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Luggage Room Relay Block Assembly - -
      *a IGCT NO. 6 Fuse Holder *b Front view of wire harness connector
      (No. 2 EV Battery Pack Wire Connector)

      Standard Resistance

      Tester Connection Condition Specified Condition
      G156-14 (IGCT) or 2 (IGCT NO. 6 fuse holder) - Body ground and other terminals Always 10 kΩ or higher
    6. Install the IGCT NO. 6 fuse to the luggage room relay block assembly.
    7. Reconnect the G156 No. 2 EV battery pack wire connector.
    8. Install the center No. 2 floor to brace extension.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE FUSE (IGCT NO. 6) 

    Result: 

    NG 

    See step  8

  8. REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    REPLACE FUSE (IGCT NO. 6)