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Home >> Lexus >> 2020 >> ES 300h Luxury >> Repair and Diagnosis >> External Pages >> Different car >> Section 64 (Blind Spot Monitor System (Except Hybrid) - Diagnostic Codes & Circuit Tests) >> BLIND SPOT MONITOR SYSTEM (for Gasoline Model) >> DTC U0232: Lost Communication with Blind Spot Monitor Slave Module [06/2018 - 09/2022] >> Procedure

DTC U0232: Lost Communication with Blind Spot Monitor Slave Module [06/2018 - 09/2022]: Procedure

WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 2024 Lexus ES 350, 2024 Lexus ES 250, 2023 Lexus ES 350, 2023 Lexus ES 250, and 2022 Lexus ES 350. However, it is still accessible from the selected car via links, so may be relevant.
  1. CONFIRM MODEL 
    1. Choose the model to be inspected.

      Result

      Result Proceed to
      w/ Parking Support Brake System A
      w/o Parking Support Brake System B

    Result: 

    B 

    See step  3

    Result: 

    A 

    See step  2

  2. CHECK DTC OUTPUT (PARKING SUPPORT BRAKE SYSTEM) 
    1. Using the Techstream, check for DTCs according to the prompts on the screen.

      Refer to DTC CHECK / CLEAR [06/2018 - 09/2022]

      Body Electrical > Advanced Parking Guidance/ICS/Intuitive P/A > Trouble Codes 

      Standard

      The clearance warning ECU assembly does not output DTCs U0232 and U0233 simultaneously.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    GO TO PARKING SUPPORT BRAKE SYSTEM (DTC U0232). Refer to  DTC U0232: Lost Communication with Blind Spot Monitor Slave Module; DTC U0233: Lost Communication with Blind Spot Monitor Master Module [06/2018 - 09/2022] 

    Result: 

    OK 

    See step  3

  3. CHECK CAN BUS MAIN WIRE 
    1. Turn the engine switch off.
    2. Disconnect the cable from the negative (-) battery terminal.
    3. Measure the resistance according to the value(s) in the table below.
      GTY807935Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 DLC3
      *a Component with harness connected
      (No. 24 CAN Junction Connector)

      Standard Resistance

      Tester Connection Condition Specified Condition Result
      N100-3 (CANH) -N100-14 (CANL) Cable disconnected from negative (-) battery terminal 54 to 69 Ω Below 54 Ω: Short circuit between bus lines
      70 Ω or more: Open circuit in main bus lines
      N100-3 (CANH) - G57-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Below 200 Ω: CANH short to ground
      N100-14 (CANL) - G57-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Below 200 Ω: CANL short to ground
      N100-3 (CANH) - G57-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Below 6 kΩ: CANH +B short
      N100-14 (CANL) - G57-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Below 6 kΩ: CANL +B short

      Result

      Result Proceed to
      OK A
      Open circuit in CAN main bus lines B
      Short circuit between bus lines C
      • Short to ground
      • +B short
      		 D

    Result: 

    B 

    See step  9

    Result: 

    C 

    See step  12

    Result: 

    D 

    See step  15

    Result: 

    A 

    See step  4

  4. CHECK HARNESS AND CONNECTOR (BLIND SPOT MONITOR SENSOR LH - BODY GROUND) 
    1. Disconnect the R5 blind spot monitor sensor LH connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      R5-10 (BLGD) - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  5

  5. CHECK HARNESS AND CONNECTOR (BLIND SPOT MONITOR SENSOR LH POWER SOURCE) 
    1. Disconnect the R5 blind spot monitor sensor LH connector.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      R5-5 (BLB) - Body ground Engine switch on (IG) 11 to 14 V
      R5-5 (BLB) - Body ground Engine switch off Below 1 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  6

  6. CHECK DTC 
    1. Reconnect the cable to the negative (-) battery terminal.
    2. Turn the engine switch off.
    3. Turn the engine switch on (IG).
    4. Check for DTCs.

      Refer to DTC CHECK / CLEAR [06/2018 - ]

      Body Electrical > Blind Spot Monitor Master > Trouble Codes 

      OK

      No DTCs are output.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [06/2018 - ] 

    Result: 

    NG 

    See step  7

  7. REPLACE BLIND SPOT MONITOR SENSOR LH 
    1. Replace the blind spot monitor sensor LH.

      Refer to REMOVAL [06/2018 - 08/2021] , or refer to REMOVAL [08/2021 - 09/2022]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  8

  8. RECHECK DTC 
    1. Clear the DTCs.

      Refer to DTC CHECK / CLEAR [06/2018 - ]

      Body Electrical > Blind Spot Monitor Master > Clear DTCs 

    2. Recheck for DTCs and check if the same DTC is output again.

      Body Electrical > Blind Spot Monitor Master > Trouble Codes 

      OK

      No DTCs are output.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    END 

    Result: 

    NG 

    REPLACE BLIND SPOT MONITOR SENSOR RH. Refer to  REMOVAL [06/2018 - 08/2021]  , or refer to  REMOVAL [08/2021 - 09/2022] 

  9. CHECK FOR OPEN IN CAN BUS MAIN WIRE (NO. 24 CAN JUNCTION CONNECTOR) 
    1. Disconnect the N100 No. 24 CAN junction connector.
      GTY835802Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to No. 24 CAN Junction Connector)
      *b to Blind Spot Monitor Sensor LH CAN main wire
      *c to Blind Spot Monitor Sensor RH CAN main wire
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      N100-3 (CANH) - N100-14 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
      N100-2 (CANH) - N100-13 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω

      Result

      Result Proceed to
      OK A
      NG (to blind spot monitor sensor LH CAN main wire) B
      NG (to blind spot monitor sensor RH CAN main wire) C

    Result: 

    A 

    REPLACE NO. 24 CAN JUNCTION CONNECTOR 

    Result: 

    C 

    See step  11

    Result: 

    B 

    See step  10

  10. CHECK FOR OPEN IN CAN BUS MAIN WIRE (BLIND SPOT MONITOR SENSOR LH) 
    1. Reconnect the N100 No. 24 CAN junction connector.
    2. Disconnect the R5 blind spot monitor sensor LH connector.
      GTY834390Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Blind Spot Monitor Sensor LH)
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      R5-1 (CA2P) - R5-6 (CA2N) Cable disconnected from negative (-) battery terminal 108 to 132 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE BLIND SPOT MONITOR SENSOR LH. Refer to  REMOVAL [06/2018 - 08/2021]  , or refer to  REMOVAL [08/2021 - 09/2022] 

    Result: 

    NG 

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (BLIND SPOT MONITOR SENSOR LH - NO. 24 CAN JUNCTION CONNECTOR) 

  11. CHECK FOR OPEN IN CAN BUS MAIN WIRE (BLIND SPOT MONITOR SENSOR RH) 
    1. Reconnect the N100 No. 24 CAN junction connector.
    2. Disconnect the R4 blind spot monitor sensor RH connector.
      GTY807620Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Blind Spot Monitor Sensor RH)
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      R4-1 (CA2P) -R4-6 (CA2N) Cable disconnected from negative (-) battery terminal 108 to 132 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE BLIND SPOT MONITOR SENSOR RH. Refer to  REMOVAL [06/2018 - 08/2021]  , or refer to  REMOVAL [08/2021 - 09/2022] 

    Result: 

    NG 

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (BLIND SPOT MONITOR SENSOR RH - NO. 24 CAN JUNCTION CONNECTOR) 

  12. CHECK FOR SHORT IN CAN BUS WIRES (NO. 24 CAN JUNCTION CONNECTOR) 
    1. Disconnect the N100 No. 24 CAN junction connector.
      GTY835802Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to No. 24 CAN Junction Connector)
      *b to Blind Spot Monitor Sensor LH CAN main wire
      *c to Blind Spot Monitor Sensor RH CAN main wire
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      N100-3 (CANH) - N100-14 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
      N100-2 (CANH) - N100-13 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω

      Result

      Result Proceed to
      OK A
      NG (to blind spot monitor sensor LH CAN main wire) B
      NG (to blind spot monitor sensor RH CAN main wire) C

    Result: 

    A 

    REPLACE NO. 24 CAN JUNCTION CONNECTOR 

    Result: 

    C 

    See step  14

    Result: 

    B 

    See step  13

  13. CHECK FOR SHORT IN CAN BUS WIRES (BLIND SPOT MONITOR SENSOR LH) 
    1. Reconnect the N100 No. 24 CAN junction connector.
    2. Disconnect the R5 blind spot monitor sensor LH connector.
      GTY834390Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Blind Spot Monitor Sensor LH)
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      R5-1 (CA2P) - R5-6 (CA2N) Cable disconnected from negative (-) battery terminal 108 to 132 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE BLIND SPOT MONITOR SENSOR LH. Refer to  REMOVAL [06/2018 - 08/2021]  , or refer to  REMOVAL [08/2021 - 09/2022] 

    Result: 

    NG 

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (BLIND SPOT MONITOR SENSOR LH - NO. 24 CAN JUNCTION CONNECTOR) 

  14. CHECK FOR SHORT IN CAN BUS WIRES (BLIND SPOT MONITOR SENSOR RH) 
    1. Reconnect the N100 No. 24 CAN junction connector.
    2. Disconnect the R4 blind spot monitor sensor RH connector.
      GTY807620Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Blind Spot Monitor Sensor RH)
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      R4-1 (CA2P) -R4-6 (CA2N) Cable disconnected from negative (-) battery terminal 108 to 132 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE BLIND SPOT MONITOR SENSOR RH. Refer to  REMOVAL [06/2018 - 08/2021]  , or refer to  REMOVAL [08/2021 - 09/2022] 

    Result: 

    NG 

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (BLIND SPOT MONITOR SENSOR RH - NO. 24 CAN JUNCTION CONNECTOR) 

  15. CHECK FOR SHORT IN CAN BUS WIRES (NO. 24 CAN JUNCTION CONNECTOR) 
    1. Disconnect the N100 No. 24 CAN junction connector.
    2. Measure the resistance according to the value(s) in the table below.
      GTY776842Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 DLC3 - -
      *a Front view of wire harness connector
      (to No. 24 CAN Junction Connector)      		 *b to Blind Spot Monitor Sensor LH CAN main wire
      *c to Blind Spot Monitor Sensor RH CAN main wire - -

      Standard Resistance

      Tester Connection Condition Specified Condition
      N100-3 (CANH) - G57-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      N100-14 (CANL) - G57-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      N100-3 (CANH) - G57-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher
      N100-14 (CANL) - G57-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher
      N100-2 (CANH) - G57-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      N100-13 (CANL) - G57-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      N100-2 (CANH) - G57-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher
      N100-13 (CANL) - G57-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher

      Result

      Result Proceed to
      OK A
      NG (to blind spot monitor sensor LH CAN main wire) B
      NG (to blind spot monitor sensor RH CAN main wire) C

    Result: 

    A 

    REPLACE NO. 24 CAN JUNCTION CONNECTOR 

    Result: 

    C 

    See step  17

    Result: 

    B 

    See step  16

  16. CHECK FOR SHORT IN CAN BUS WIRES (BLIND SPOT MONITOR SENSOR LH) 
    1. Reconnect the N100 No. 24 CAN junction connector.
    2. Disconnect the R5 blind spot monitor sensor LH connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      R5-1 (CA2P) - G57-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      R5-6 (CA2N) - G57-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      R5-1 (CA2P) - G57-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher
      R5-6 (CA2N) - G57-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher
      GTY800779Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 DLC3
      *a Front view of wire harness connector
      (to Blind Spot Monitor Sensor LH)

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE BLIND SPOT MONITOR SENSOR LH. Refer to  REMOVAL [06/2018 - 08/2021]  , or refer to  REMOVAL [08/2021 - 09/2022] 

    Result: 

    NG 

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (BLIND SPOT MONITOR SENSOR LH - NO. 24 CAN JUNCTION CONNECTOR) 

  17. CHECK FOR SHORT IN CAN BUS WIRES (BLIND SPOT MONITOR SENSOR RH) 
    1. Reconnect the N100 No. 24 CAN junction connector.
    2. Disconnect the R4 blind spot monitor sensor RH connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      R4-1 (CA2P) - G57-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      R4-6 (CA2N) - G57-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      R4-1 (CA2P) - G57-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher
      R4-6 (CA2N) - G57-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher
      GTY800774Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 DLC3
      *a Front view of wire harness connector
      (to Blind Spot Monitor Sensor RH)

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE BLIND SPOT MONITOR SENSOR RH. Refer to  REMOVAL [06/2018 - 08/2021]  , or refer to  REMOVAL [08/2021 - 09/2022] 

    Result: 

    NG 

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (BLIND SPOT MONITOR SENSOR RH - NO. 24 CAN JUNCTION CONNECTOR) 

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