LEMON Manuals: Even more car manuals for everyone
Home >> Lexus >> 2020 >> UX 200 Luxury >> Repair and Diagnosis >> External Pages >> Different car >> Section 44 (Hybrid Control System (Diagnostic Codes (5 Of 5) & Circuit Tests)) >> Hybrid Control System >> ECU Power Source Circuit [10/2018 - ] >> Procedure

ECU Power Source Circuit [10/2018 - ]: Procedure

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2024 Lexus UX 250h, 2023 Lexus UX 250h, 2022 Lexus UX 250h, 2021 Lexus UX 250h, and 2020 Lexus UX 250h. However, it is still accessible from the selected car via links, so may be relevant.
  1. CHECK HYBRID VEHICLE CONTROL ECU (+B1, +B2 VOLTAGE) 
    1. Turn the power switch on (IG).
    2. Measure the voltage according to the value(s) in the table below.
      GTY780610Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Hybrid Vehicle Control ECU)      		 - -

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      A46-11 (+B1) - Body ground Power switch on (IG) 11 to 14 V
      F59-1 (+B2) - Body ground Power switch on (IG) 11 to 14 V
    3. Turn the power 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 F60 and F59 hybrid vehicle control ECU connectors.
    2. Measure the resistance according to the value(s) in the table below.
      GTY797148Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Hybrid Vehicle Control ECU)      		 - -

      Standard Resistance

      Tester Connection Condition Specified Condition
      F59-3 (E1) - Body ground Always Below 1 Ω
      F60-34 (E12) - Body ground Always Below 1 Ω
      F60-12 (E01) - Body ground Always Below 1 Ω
      F60-11 (E02) - Body ground Always Below 1 Ω
    3. Reconnect the F60 and F59 hybrid vehicle control ECU connectors.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    GO TO PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [10/2018 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  3. CHECK HYBRID VEHICLE CONTROL ECU (MREL VOLTAGE) 
    1. Turn the power switch on (IG).
    2. Measure the voltage according to the value(s) in the table below.
      GTY780603Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Hybrid Vehicle Control ECU)      		 - -

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      A46-5 (MREL) - Body ground Power switch on (IG) 11 to 14 V
    3. Turn the power switch off.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE HYBRID VEHICLE CONTROL ECU. Refer to  REMOVAL [10/2018 - 07/2022]  Refer to  REMOVAL [07/2022 - ] 

    Result: 

    OK 

    See step  4

  4. CHECK FUSE (PM-IGCT) 
    1. Remove the PM-IGCT fuse from the No. 3 relay block.
      GTY777956Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 3 Relay Block
      *2 PM-IGCT Fuse
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

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

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  13

    Result: 

    OK 

    See step  5

  5. CHECK FUSE (IGCT IG) 
    1. Disconnect the cable from the negative (-) auxiliary battery terminal.
    2. Check the fusible link block assembly (IGCT IG) for improper installation.
      GTY776894Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 Fusible Link Block Assembly

      OK

      The fusible link block assembly is installed securely and there is no contact problem.

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      A-1 (Fusible Link Block Assembly) - N114-1 (Fusible Link Block Assembly) Always Below 1 Ω
    4. Reconnect the cable from the negative (-) auxiliary battery terminal.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  11

    Result: 

    OK 

    See step  6

  6. INSPECT RELAY (IGCT) 
    1. Remove the IGCT relay from the No. 1 engine room relay block.
      GTY802806Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 NO. 3 RELAY BLOCK
      *2 IGCT Relay
    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 (NO. 3 RELAY BLOCK - HYBRID VEHICLE CONTROL ECU) 
    1. Disconnect the A46 and F59 hybrid vehicle control ECU connectors.
    2. Remove the PM-IGCT fuse from the No. 3 relay block.
    3. Measure the resistance according to the value(s) in the table below.
      GTY820985Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 NO. 3 RELAY BLOCK *2 PM-IGCT Fuse Holder
      *a Front view of wire harness connector
      (to Hybrid Vehicle Control ECU)      		 - -

      Standard Resistance

      Tester Connection Condition Specified Condition
      A46-11 (+B1) - 2 (PM-IGCT fuse holder) Always Below 1 Ω
      F59-1 (+B2) - 2 (PM-IGCT fuse holder) Always Below 1 Ω
    4. Reconnect the A46 and F59 hybrid vehicle control ECU connectors.
    5. Install the PM-IGCT fuse.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  8

  8. CHECK HARNESS AND CONNECTOR (NO. 3 RELAY BLOCK - FUSIBLE LINK BLOCK ASSEMBLY) 
    1. Disconnect the PM-IGCT Fuse, IGCT relay from the No. 3 relay block.
      GTY821070Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 NO. 3 RELAY BLOCK
      *2 PM-IGCT Fuse Holder
      *3 IGCT Relay Holder
      *4 Fusible Link 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) - N114-1 (Fusible Link Block Assembly) Always Below 1 Ω
      5 (IGCT relay holder) - 1 (PM-IGCT fuse holder) Always Below 1 Ω
    3. Install the IGCT-IG 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. 3 RELAY BLOCK) 
    1. Disconnect the A46 hybrid vehicle control ECU connector.
    2. Remove the IGCT relay from the No. 3 relay block.
    3. Measure the resistance according to the value(s) in the table below.
      GTY789301Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 NO. 3 RELAY BLOCK *2 IGCT Relay Holder
      *a Front view of wire harness connector
      (to Hybrid Vehicle Control ECU)      		 - -

      Standard Resistance

      Tester Connection Condition Specified Condition
      A46-5 (MREL) - 1 (IGCT relay) Always Below 1 Ω
      A46-5 (MREL) or 1 (IGCT relay) - Body ground and other terminals Always 10 kΩ or higher
    4. Install the IGCT relay.
    5. Reconnect the A46 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. 3 RELAY BLOCK - BODY GROUND) 
    1. Remove the IGCT relay from the No. 3 relay block.
      GTY799118Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 3 Relay Block
      *2 IGCT Relay Holder
    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 [10/2018 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  11. CHECK HARNESS AND CONNECTOR (NO. 3 RELAY BLOCK - FUSIBLE LINK BLOCK ASSEMBLY) 
    1. Disconnect the PM-IGCT Fuse, IGCT relay from the No. 3 relay block.
      GTY821070Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 NO. 3 RELAY BLOCK
      *2 PM-IGCT Fuse Holder
      *3 IGCT Relay Holder
      *4 Fusible Link 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 N114-1 (Fusible Link Block Assembly) - Body ground and other terminals Always 10 kΩ or higher
      5 (IGCT relay holder) or 1 (PM-IGCT fuse holder) - Body ground and other terminals Always 10 kΩ or higher
    3. Install the IGCT-IG fuse, PM-IGCT fuse and IGCT relay.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE FUSIBLE LINK BLOCK ASSEMBLY (IGCT-IG) 

    Result: 

    NG 

    See step  12

  12. REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    REPLACE FUSIBLE LINK BLOCK ASSEMBLY (IGCT-IG) 

  13. CHECK HARNESS AND CONNECTOR (NO. 3 RELAY BLOCK - HYBRID VEHICLE CONTROL ECU) 
    1. Remove the PM-IGCT fuse from the No. 3 relay block.
    2. Disconnect the A46 and F59 hybrid vehicle control ECU connectors.
    3. Measure the resistance according to the value(s) in the table below.
      GTY820986Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 No. 3 Relay Block *2 PM-IGCT Fuse Holder
      *a Front view of wire harness connector
      (to Hybrid Vehicle Control ECU)      		 - -

      Standard Resistance

      Tester Connection Condition Specified Condition
      A46-11 (+B1) or 2 (PM-IGCT fuse holder) - Body ground and other terminals Always 10 kΩ or higher
      F59-1 (+B2) or 2 (PM-IGCT fuse holder) - Body ground and other terminals Always 10 kΩ or higher
    4. Reconnect the A46 and F59 hybrid vehicle control ECU connectors.
    5. Install the PM-IGCT fuse.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE FUSE (PM-IGCT) 

    Result: 

    NG 

    See step  14

  14. REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result

    Proceed to
    NEXT

    Result: 

    NEXT 

    REPLACE FUSE (PM-IGCT) 

scientia non olet · About LEMON Manuals