CAN COMMUNICATION SYSTEM(for LHD) Check Bus 5 Line for Short to GND

DESCRIPTION

There may be a short circuit between one of the CAN bus wires and GND when no resistance exists between terminal 15 (CA5H) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3, or terminal 16 (CA5L) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3.

Symptom Trouble Area
No resistance exists between terminal 15 (CA5H) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3, or terminal 16 (CA5L) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3.

  • Short to GND in bus 5 CAN main wires

  • Short to GND in bus 5 CAN branch wires

  • Central gateway ECU (network gateway ECU)

  • Millimeter wave radar sensor assembly*1

  • Driving support ECU assembly*1

  • Forward recognition camera*1

  • Clearance warning ECU assembly*2

  • Blind spot monitor sensor RH*3

  • No. 1 CAN junction connector

  • No. 5 CAN junction connector

  • No. 13 junction connector

WIRING DIAGRAM

B002ER8E02

CAUTION / NOTICE / HINT

Note


  • Before measuring the resistance of the CAN bus, turn the engine switch off and leave the vehicle for 1 minute or more without operating the key or any switches, or opening or closing the doors. After that, disconnect the cable from the negative (-) battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.

  • After turning the engine switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) battery terminal notices before proceeding with work.

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  • Because the order of diagnosis is important to allow correct diagnosis, make sure to begin troubleshooting using How to Proceed with Troubleshooting when CAN communication system related DTCs are output.

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  • After performing repairs, perform the DTC check procedure and confirm that the DTCs are not output again.

  • DTC check procedure: Turn the engine switch on (IG), wait at least 60 seconds, and then drive the vehicle at a speed of 40 km/h (25 mph) or more for 5 minutes or more.

  • After the repair, perform the CAN bus check and check that all the ECUs and sensors connected to the CAN communication system are displayed as normal.

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Tech Tips


  • Operating the engine switch, any other switches or a door triggers related ECU and sensor communication on the CAN. This communication will cause the resistance value to change.

  • Even after DTCs are cleared, if a DTC is stored again after driving the vehicle for a while, the malfunction may be occurring due to vibration of the vehicle. In such a case, wiggling the ECUs or wire harness while performing the inspection below may help determine the cause of the malfunction.

PROCEDURE


  1. CHECK FOR SHORT TO GND IN CAN BUS WIRE (CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) - NO. 1 CAN JUNCTION CONNECTOR AND NO. 13 JUNCTION CONNECTOR)


    1. Disconnect the cable from negative (-) battery terminal.

    2. B002C8VC48
      *a

      Front view of wire harness connector

      (to Central Gateway ECU (Network Gateway ECU))
      *b Front view of DLC3

      Disconnect the central gateway ECU (network gateway ECU) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      K66-15 (CA5H) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      K66-16 (CA5L) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      K66-9 (CAXH) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      K66-24 (CAXL) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) Click here

    NG

  2. CONNECT CONNECTOR


    1. Reconnect the K66 central gateway ECU (network gateway ECU) connector.

      Result
      Proceed to
      NEXT

    NEXT

  3. CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 1 CAN JUNCTION CONNECTOR)


    1. Disconnect the No. 1 CAN junction connector.

      B002CSWC18
      *a

      Front view of wire harness connector

      (to No. 1 CAN Junction Connector)

      		 *b Front view of DLC3
      *c to Millimeter Wave Radar Sensor Assembly (w/ Pre-crash Safety System) *d to No. 5 CAN Junction Connector
      *e to Central Gateway ECU (Network Gateway ECU) (CA5H and CA5L Terminal) - -

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      A39-8 (CANH) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Millimeter wave radar sensor assembly*1
      A39-19 (CANL) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      A39-9 (CANH) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher No. 5 CAN junction connector
      A39-20 (CANL) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      A39-10 (CANH) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Central gateway ECU (network gateway ECU) (CA5H and CA5L terminal)
      A39-21 (CANL) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher

      • *1: w/ Pre-crash Safety System

      Result
      Result Proceed to
      OK A
      NG (Central gateway ECU (network gateway ECU) CAN main wire) B
      NG (No. 5 CAN junction connector CAN main wire) C
      NG (ECU or sensor CAN branch wire) D

    A

    REPLACE NO. 1 CAN JUNCTION CONNECTOR

    B

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 1 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))

    D

    GO TO STEP 8 Click here

    C

  4. CONNECT CONNECTOR


    1. Reconnect the A39 No. 1 CAN junction connector.

      Result
      Proceed to
      NEXT

    NEXT

  5. CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 5 CAN JUNCTION CONNECTOR)


    1. Disconnect the No. 5 CAN junction connector.

      B002CSWC19
      *a

      Front view of wire harness connector

      (to No. 5 CAN Junction Connector)

      		 *b Front view of DLC3
      *c to No. 13 Junction Connector *d to No. 1 CAN Junction Connector
      *e to Driving Support ECU Assembly (w/ Pre-crash Safety System) *f to Clearance Warning ECU Assembly (w/ LEXUS Parking Assist-sensor System)
      *g to Forward Recognition Camera (w/ Pre-crash Safety System) - -

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      K107-3 (CANH) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher No. 13 junction connector
      K107-14 (CANL) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      K107-4 (CANH) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher No. 1 CAN junction connector
      K107-15 (CANL) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      K107-8 (CANH) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Driving support ECU assembly*1
      K107-19 (CANL) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      K107-9 (CANH) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Clearance warning ECU assembly*2
      K107-20 (CANL) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      K107-10 (CANH) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Forward recognition camera*1
      K107-21 (CANL) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher

      • *1: w/ Pre-crash Safety System

      • *2: w/ LEXUS Parking Assist-sensor System

      Result
      Result Proceed to
      OK A
      NG (No. 1 CAN junction connector CAN main wire) B
      NG (No. 13 junction connector CAN main wire) C
      NG (ECU or sensor CAN branch wires) D

    A

    REPLACE NO. 5 CAN JUNCTION CONNECTOR

    B

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 1 CAN JUNCTION CONNECTOR - NO. 5 CAN JUNCTION CONNECTOR)

    D

    GO TO STEP 8 Click here

    C

  6. CONNECT CONNECTOR


    1. Reconnect the K107 No. 5 CAN junction connector.

      Result
      Proceed to
      NEXT

    NEXT

  7. CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 13 JUNCTION CONNECTOR)


    1. Disconnect the No. 13 junction connector.

      B002CSWC51
      *a

      Front view of wire harness connector

      (to No. 13 Junction Connector)

      		 *b Front view of DLC3
      *c to No. 5 CAN Junction Connector *d to Central Gateway ECU (Network Gateway ECU) (CAXH and CAXL Terminal)
      *e to Blind Spot Monitor Sensor RH (w/ Blind Spot Monitor System) - -

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      T40-8 (CANH) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher No. 5 CAN junction connector
      T40-19 (CANL) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      T40-9 (CANH) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Central gateway ECU (network gateway ECU) (CAXH and CAXL terminal)
      T40-20 (CANL) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      T40-10 (CANH) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Blind spot monitor sensor RH*1
      T40-21 (CANL) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher

      • *1: w/ Blind Spot Monitor System

      Result
      Result Proceed to
      OK A
      NG (central gateway ECU (network gateway ECU) CAN main wire) B
      NG (No. 5 CAN junction connector CAN main wire) C
      NG (ECU or sensor CAN branch wires) D

    A

    REPLACE NO. 13 JUNCTION CONNECTOR

    B

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 13 JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))

    C

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 5 CAN JUNCTION CONNECTOR - NO. 13 JUNCTION CONNECTOR)

    D

  8. CHECK FOR SHORT TO GND IN CAN BUS WIRE (ECU, SENSOR)


    1. B002ELMC68
      *a

      Component with harness connected

      (Central Gateway ECU (Network Gateway ECU))
      *b Front view of DLC3

      Reconnect the CAN junction connector.

    2. Disconnect the connector that includes terminals CANH and CANL from the ECU or sensor to which the short to GND is connected.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      K66-15 (CA5H) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      K66-16 (CA5L) - K16-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher

      Tech Tips

      If the resistance changes to 200 Ω or higher when the connector is disconnected from the ECU or sensor, there may be a short in the ECU or sensor.

      Result
      Proceed to
      OK
      NG

    OK

    REPAIR OR REPLACE CORRESPONDING ECU OR SENSOR CAN BRANCH WIRES OR CONNECTOR

    NG

    REPLACE CORRESPONDING ECU OR SENSOR