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Home >> Toyota >> 2021 >> Highlander LE, 4WD >> Repair and Diagnosis >> Accessories & Equipment >> Collision/Avoidance >> Blind Spot Monitor System - Diagnostic Codes & Symptom Tests >> Blind Spot Monitor System >> DTC U0232: Lost Communication with Blind Spot Monitor Slave Module [12/2019 - 11/2023] >> Procedure

DTC U0232: Lost Communication with Blind Spot Monitor Slave Module [12/2019 - 11/2023]: Procedure

  1. CONFIRM MODEL 
    1. Choose the model to be inspected.

      Result

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

    Result: 

    B 

    See step  3

    Result: 

    A 

    See step  2

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

      Refer to DTC CHECK / CLEAR [12/2019 - 11/2023]

      Body Electrical > Clearance Warning > Trouble Codes 

      Standard

      The clearance warning ECU assembly does not output DTCs U1177-87 and U1178-87 simultaneously.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    GO TO PARKING SUPPORT BRAKE SYSTEM (DTC U1177-87). Refer to  DTC U1177-87: Lost Communication with Side Obstacle Detection Control Module "A" (ch2) Missing Message; DTC U1178-87: Lost Communication with Side Obstacle Detection Control Module "B" (ch2) Missing Message [12/2019 - 11/2023] 

    Result: 

    OK 

    See step  3

  3. CHECK CAN BUS MAIN WIRE 
    1. Turn the ignition switch off.
    2. Disconnect the cable from the negative (-) auxiliary battery terminal.
    3. Measure the resistance according to the value(s) in the table below.
      GTY866466Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 DLC3
      *a Component with harness connected
      (No. 22 CAN Junction Connector)

      Standard Resistance

      Tester Connection Condition Specified Condition Result
      M34-1 (CANH) - M34-12 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 54 to 69 Ω Below 54 Ω: Short circuit between bus lines
      70 Ω or more: Open circuit in main bus lines
      M34-1 (CANH) - H56-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Below 200 Ω: CANH short to ground
      M34-12 (CANL) - H56-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Below 200 Ω: CANL short to ground
      M34-1 (CANH) - H56-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Below 6 kΩ: CANH +B short
      M34-12 (CANL) - H56-16 (BAT) Cable disconnected from negative (-) auxiliary 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 RH (SLAVE) - BODY GROUND) 
    1. Disconnect the M2 blind spot monitor sensor RH (slave) connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      M2-10 (BRGD) - 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 RH (SLAVE) POWER SOURCE) 
    1. Disconnect the M2 blind spot monitor sensor RH (slave) connector.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      M2-5 (BRB) - Body ground Ignition switch ON 11 to 14 V*1
      10.5 to 16 V*2
      M2-5 (BRB) - Body ground Ignition switch off Below 1 V
      GTY944467Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Blind Spot Monitor Sensor RH (Slave))
      1. *1: w/o Stop and Start System
      2. *2: w/ Stop and Start System

      Result

      Result Proceed to
      OK A
      NG (w/o Stop and Start System) B
      NG (w/ Stop and Start System) C

    Result: 

    B 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    C 

    GO TO STOP AND START SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [12/2019 - 10/2022]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2022 - ] 

    Result: 

    A 

    See step  6

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

      Refer to DTC CHECK / CLEAR [12/2019 - 11/2023]

      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 [12/2019 - ] 

    Result: 

    NG 

    See step  7

  7. REPLACE BLIND SPOT MONITOR SENSOR RH (SLAVE) 
    1. Refer to REMOVAL [12/2019 - 10/2022] , or refer to REMOVAL [10/2022 - 11/2023]

      Result

      Proceed to
      NEXT

    Result: 

    NEXT 

    See step  8

  8. RECHECK DTC 
    1. Clear the DTCs.

      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 LH (MASTER). Refer to  REMOVAL [12/2019 - 10/2022]  , or refer to  REMOVAL [10/2022 - 11/2023] 

  9. CHECK FOR OPEN IN CAN BUS MAIN WIRE (NO. 22 CAN JUNCTION CONNECTOR) 
    1. Disconnect the No. 22 CAN junction connector.
      GTY933315Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to No. 22 CAN Junction Connector)
      *b to Blind Spot Monitor Sensor LH (Master) CAN Main Wire
      *c to Blind Spot Monitor Sensor RH (Slave) CAN Main Wire
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      M34-1 (CANH) - M34-12 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω
      M34-2 (CANH) - M34-13 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω

      Result

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

    Result: 

    A 

    REPLACE NO. 22 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 (MASTER)) 
    1. Reconnect the M34 No. 22 CAN junction connector.
    2. Disconnect the M43 blind spot monitor sensor LH (master) connector.
      GTY921065Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Blind Spot Monitor Sensor LH (Master))
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      M43-1 (CA2P) - M43-6 (CA2N) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE BLIND SPOT MONITOR SENSOR LH (MASTER). Refer to  REMOVAL [12/2019 - 10/2022]  , or refer to  REMOVAL [10/2022 - 11/2023] 

    Result: 

    NG 

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (BLIND SPOT MONITOR SENSOR LH (MASTER) - NO. 22 CAN JUNCTION CONNECTOR) 

  11. CHECK FOR OPEN IN CAN BUS MAIN WIRE (BLIND SPOT MONITOR SENSOR RH (SLAVE)) 
    1. Reconnect the M34 No. 22 CAN junction connector.
    2. Disconnect the M2 blind spot monitor sensor RH (slave) connector.
      GTY921064Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Blind Spot Monitor Sensor RH (Slave))
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      M2-1 (CA2P) -M2-6 (CA2N) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE BLIND SPOT MONITOR SENSOR RH (SLAVE). Refer to  REMOVAL [12/2019 - 10/2022]  , or refer to  REMOVAL [10/2022 - 11/2023] 

    Result: 

    NG 

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (BLIND SPOT MONITOR SENSOR RH (SLAVE) - NO. 22 CAN JUNCTION CONNECTOR) 

  12. CHECK FOR SHORT IN CAN BUS WIRES (NO. 22 CAN JUNCTION CONNECTOR) 
    1. Disconnect the No. 22 CAN junction connector.
      GTY870600Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to No. 22 CAN Junction Connector)
      *b to Blind Spot Monitor Sensor LH (Master) CAN Main Wire
      *c to Blind Spot Monitor Sensor RH (Slave) CAN Main Wire
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      M34-2 (CANH) - M34-13 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω
      M34-1 (CANH) - M34-12 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω

      Result

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

    Result: 

    A 

    REPLACE NO. 22 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 (MASTER)) 
    1. Reconnect the M34 No. 22 CAN junction connector.
    2. Disconnect the M43 blind spot monitor sensor LH (master) connector.
      GTY921065Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Blind Spot Monitor Sensor LH (Master))
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      M43-1 (CA2P) - M43-6 (CA2N) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE BLIND SPOT MONITOR SENSOR LH (MASTER). Refer to  REMOVAL [12/2019 - 10/2022]  , or refer to  REMOVAL [10/2022 - 11/2023] 

    Result: 

    NG 

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (BLIND SPOT MONITOR SENSOR LH (MASTER) - NO. 22 CAN JUNCTION CONNECTOR) 

  14. CHECK FOR SHORT IN CAN BUS WIRES (BLIND SPOT MONITOR SENSOR RH (SLAVE)) 
    1. Reconnect the M34 No. 22 CAN junction connector.
    2. Disconnect the M2 blind spot monitor sensor RH (slave) connector.
      GTY921064Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Blind Spot Monitor Sensor RH (Slave))
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      M2-1 (CA2P) - M2-6 (CA2N) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE BLIND SPOT MONITOR SENSOR RH (SLAVE). Refer to  REMOVAL [12/2019 - 10/2022]  , or refer to  REMOVAL [10/2022 - 11/2023] 

    Result: 

    NG 

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (BLIND SPOT MONITOR SENSOR RH (SLAVE) - NO. 22 CAN JUNCTION CONNECTOR) 

  15. CHECK FOR SHORT IN CAN BUS WIRES (NO. 22 CAN JUNCTION CONNECTOR) 
    1. Disconnect the No. 22 CAN junction connector.
    2. Measure the resistance according to the value(s) in the table below.
      GTY838866Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 DLC3 - -
      *a Front view of wire harness connector
      (to No. 22 CAN Junction Connector)      		 *b to Blind Spot Monitor Sensor LH (Slave) CAN Main Wire
      *c to Blind Spot Monitor Sensor RH (Slave) CAN Main Wire - -

      Standard Resistance

      Tester Connection Condition Specified Condition
      M34-1 (CANH) - H56-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      M34-12 (CANL) - H56-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      M34-1 (CANH) - H56-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      M34-12 (CANL) - H56-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      M34-2 (CANH) - H56-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      M34-13 (CANL) - H56-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      M34-2 (CANH) - H56-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      M34-13 (CANL) - H56-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher

      Result

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

    Result: 

    A 

    REPLACE NO. 22 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 (MASTER)) 
    1. Reconnect the M34 No. 22 CAN junction connector.
    2. Disconnect the M43 blind spot monitor sensor LH (master) connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      M43-1 (CA2P) - H56-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      M43-6 (CA2N) - H56-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      M43-1 (CA2P) - H56-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      M43-6 (CA2N) - H56-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      GTY866925Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 DLC3
      *a Front view of wire harness connector
      (to Blind Spot Monitor Sensor LH (Master))

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE BLIND SPOT MONITOR SENSOR LH (MASTER). Refer to  REMOVAL [12/2019 - 10/2022]  , or refer to  REMOVAL [10/2022 - 11/2023] 

    Result: 

    NG 

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (BLIND SPOT MONITOR SENSOR LH (MASTER) - NO. 22 CAN JUNCTION CONNECTOR) 

  17. CHECK FOR SHORT IN CAN BUS WIRES (BLIND SPOT MONITOR SENSOR RH (SLAVE)) 
    1. Reconnect the M34 No. 22 CAN junction connector.
    2. Disconnect the M2 blind spot monitor sensor RH (slave) connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      M2-1 (CA2P) - H56-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      M2-6 (CA2N) - H56-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      M2-1 (CA2P) - H56-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      M2-6 (CA2N) - H56-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      GTY866924Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *1 DLC3
      *a Front view of wire harness connector
      (to Blind Spot Monitor Sensor RH (Slave))

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE BLIND SPOT MONITOR SENSOR RH (SLAVE). Refer to  REMOVAL [12/2019 - 10/2022]  , or refer to  REMOVAL [10/2022 - 11/2023] 

    Result: 

    NG 

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (BLIND SPOT MONITOR SENSOR RH (SLAVE) - NO. 22 CAN JUNCTION CONNECTOR) 

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