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Home >> Toyota >> 2021 >> Prius 2020 Edition >> Repair and Diagnosis >> External Pages >> Different car >> Section 264 (Hybrid Battery System - Diagnostic Codes (P1AC4-U1150) & Circuit Tests (Lithium-Ion)) >> HYBRID BATTERY SYSTEM (for LITHIUM-ION BATTERY) >> ECU Power Source Circuit [08/2020 - ] >> Procedure

ECU Power Source Circuit [08/2020 - ]: Procedure

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  1. CHECK BATTERY ECU ASSEMBLY (IGCT VOLTAGE) 
    WARNING:

    Be sure to wear insulated gloves and protective goggles.

    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 information because this may cause a malfunction.

    2. Remove the No. 1 HV battery hose.

      Refer to PROCEDURE - Step 21 [08/2020 - 08/2021] , or refer to PROCEDURE - Step 21 [08/2021 - ]

    3. Disconnect the y15 battery ECU assembly connector.
      NOTE:

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

      GTY993603Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    4. Connect the cable to the negative (-) auxiliary battery terminal.
    5. Turn the power switch on (IG).
    6. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      y15-13 (IGCT) - Body ground Power switch on (IG) 11 to 14 V
      GTY993849Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Battery ECU Assembly)
      NOTE:
      • Turning the power switch on (IG) with the service plug grip removed causes other DTCs to be stored. Clear the DTCs after performing this inspection.
      • If the power switch is turned on (IG) with the connectors disconnected, other DTCs will be stored. Be sure to clear the DTCs after the inspection.
    7. Turn the power switch off.
    8. Disconnect the cable from the negative (-) auxiliary battery terminal.
    9. Reconnect the y15 battery ECU assembly connector.
    10. Install the No. 1 HV battery hose.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  3

    Result: 

    OK 

    See step  2

  2. CHECK HARNESS AND CONNECTOR (BATTERY ECU ASSEMBLY - BODY GROUND) 
    WARNING:

    Be sure to wear insulated gloves and protective goggles.

    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 information because this may cause a malfunction.

    2. Remove the No. 1 HV battery hose.

      Refer to PROCEDURE - Step 21 [08/2020 - 08/2021] , or refer to PROCEDURE - Step 21 [08/2021 - ]

    3. Disconnect the y15 battery ECU assembly connector.
      NOTE:

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

      GTY993603Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      y15-27 (GND) - Body ground Always Below 1 Ω
      y15-3 (GND1) - Body ground Always Below 1 Ω
      y15-4 (ERTH) - Body ground Always Below 1 Ω
      GTY993810Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Battery ECU Assembly)
    5. Reconnect the y15 battery ECU assembly connector.
    6. Install the No. 1 HV battery hose.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    GO TO PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [08/2020 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  3. CHECK FUSE (IGCT NO. 2) 
    1. Remove the IGCT NO. 2 fuse from the No. 4 relay block.
      GTY749020Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 4 Relay Block
      *2 IGCT NO. 2 Fuse
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      IGCT NO. 2 fuse Always Below 1 Ω
    3. Install the IGCT NO. 2 fuse.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  6

    Result: 

    OK 

    See step  4

  4. CHECK HARNESS AND CONNECTOR (NO. 4 RELAY BLOCK - BATTERY ECU ASSEMBLY) 
    WARNING:

    Be sure to wear insulated gloves and protective goggles.

    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 information because this may cause a malfunction.

    2. Remove the No. 1 HV battery hose.

      Refer to PROCEDURE - Step 21 [08/2020 - 08/2021] , or refer to PROCEDURE - Step 21 [08/2021 - ]

    3. Disconnect the y15 battery ECU assembly connector.
      NOTE:

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

      GTY993603Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    4. Remove the IGCT NO. 2 fuse from the No. 4 relay block.
    5. Measure the resistance according to the value(s) in the table below.
      GTY993815Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 4 Relay Block *2 IGCT NO. 2 Fuse Holder
      *a Front view of wire harness connector
      (to Battery ECU Assembly)      		 - -

      Standard Resistance

      Tester Connection Condition Specified Condition
      y15-13 (IGCT) - 2 (IGCT NO. 2 fuse holder) Always Below 1 Ω
    6. Install the IGCT NO. 2 fuse.
    7. Reconnect the y15 battery ECU assembly connector.
    8. Install the No. 1 HV battery hose.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  5

  5. CHECK HARNESS AND CONNECTOR (NO. 3 RELAY BLOCK - NO. 4 RELAY BLOCK) 
    1. Remove the IGCT NO. 2 fuse from the No. 4 relay block.
    2. Remove the IGCT relay from the No. 3 relay block.
    3. Measure the resistance according to the value(s) in the table below.
      GTY993994Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 4 Relay Block *2 No. 3 Relay Block
      *3 IGCT NO. 2 Fuse Holder *4 IGCT Relay Holder

      Standard Resistance

      Tester Connection Condition Specified Condition
      5 (IGCT relay holder 5) - 1 (IGCT NO. 2 fuse holder 1) Always Below 1 Ω
    4. Install the IGCT relay.
    5. Install the IGCT NO. 2 fuse.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    CHECK ECU Power Source Circuit (HYBRID CONTROL SYSTEM (for LITHIUM-ION BATTERY)). Refer to  ECU Power Source Circuit [08/2020 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  6. CHECK HARNESS AND CONNECTOR (NO. 4 RELAY BLOCK - BATTERY ECU ASSEMBLY) 
    WARNING:

    Be sure to wear insulated gloves and protective goggles.

    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 information because this may cause a malfunction.

    2. Remove the No. 1 HV battery hose.

      Refer to PROCEDURE - Step 21 [08/2020 - 08/2021] , or refer to PROCEDURE - Step 21 [08/2021 - ]

    3. Disconnect the y15 battery ECU assembly connector.
      NOTE:

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

      GTY993603Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    4. Remove the IGCT NO. 2 fuse from the No. 4 relay block.
    5. Measure the resistance according to the value(s) in the table below.
      GTY993815Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 4 Relay Block *2 IGCT NO. 2 Fuse Holder
      *a Front view of wire harness connector
      (to Battery ECU Assembly)      		 - -

      Standard Resistance

      Tester Connection Condition Specified Condition
      y15-13 (IGCT) or 2 (IGCT-NO. 2 fuse holder) - Body ground and other terminals Always 10 kΩ or higher
    6. Install the IGCT NO. 2 fuse.
    7. Reconnect the y15 battery ECU assembly connector.
    8. Install the No. 1 HV battery hose.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE FUSE (IGCT NO. 2) 

    Result: 

    NG 

    See step  7

  7. REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    REPLACE FUSE (IGCT NO. 2) 

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