CAN COMMUNICATION SYSTEM(for RHD) 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 and terminal 4 (CG) of the DLC3, or terminal 16 (CA5L) of the central gateway ECU and terminal 4 (CG) of the DLC3.

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

  • Power management control ECU

  • Headlight ECU sub-assembly LH

  • Absorber control ECU*1

  • Driving support ECU assembly*2

  • Forward recognition camera*2

  • Millimeter wave radar sensor assembly*2

  • Clearance warning ECU assembly*3

  • Blind Spot Monitor Sensor RH*4

  • No. 4 CAN junction connector

  • No. 8 CAN junction connector

  • No. 9 CAN junction connector

WIRING DIAGRAM

B002C1HE03
B002BH0E02

CAUTION / NOTICE / HINT

Note


  • 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 Click here.

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

  • After turning the power switch off, waiting time may be required before disconnecting the cable from the auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the auxiliary battery terminal notice before proceeding with work Click here.

  • After the repair, perform CAN Bus Check and check that all the ECUs and sensors connected to the CAN communication system are displayed Click here.

Tech Tips


  • Operating the power switch, any switches or any doors triggers related ECU and sensor communication with the CAN, which causes resistance variation.

  • 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 (NO. 9 CAN JUNCTION CONNECTOR)


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

      A000PLEE02
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to No. 9 CAN Junction Connector)

      		 *b Front view of DLC3
      *c to Central Gateway ECU *d to No. 4 CAN Junction Connector
      *e to Power Management Control ECU *f to Headlight ECU Sub-assembly LH
      *g to Clearance Warning ECU Assembly (w/ LEXUS Parking Assist-sensor System) *h to Forward Recognition Camera (w/ Pre-crash Safety System)
      *i to Millimeter Wave Radar Sensor Assembly (w/ Pre-crash Safety System) - -

    2. Disconnect the No. 9 CAN junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connect to
      N131-4 (CANH) - N20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Central gateway ECU
      N131-15 (CANL) - N20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      N131-5 (CANH) - N20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher No. 4 CAN junction connector
      N131-16 (CANL) - N20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      N131-7 (CANH) - N20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Power management control ECU
      N131-18 (CANL) - N20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      N131-8 (CANH) - N20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Headlight ECU sub-assembly LH
      N131-19 (CANL) - N20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      N131-9 (CANH) - N20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Clearance warning ECU assembly*1
      N131-20 (CANL) - N20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      N131-10 (CANH) - N20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Forward recognition camera*2
      N131-21 (CANL) - N20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      N131-11 (CANH) - N20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Millimeter wave radar sensor assembly*2
      N131-22 (CANL) - N20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher

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

      • *2: w/ Pre-crash Safety System

      Result
      Result Proceed to
      OK A
      NG (Central gateway ECU CAN main wire) B
      NG (No. 4 CAN junction connector CAN main wire) C
      NG (ECU or sensor CAN branch wires) D

    A

    REPLACE NO. 9 CAN JUNCTION CONNECTOR

    C

    CONNECT CONNECTOR Click here

    D

    CHECK FOR SHORT TO GND IN CAN BUS WIRE (ECU, SENSOR) Click here

    B

  2. CONNECT CONNECTOR


    1. Reconnect the N131 No. 9 CAN junction connector.


    NEXT

  3. CHECK FOR SHORT TO GND IN CAN BUS WIRE (CENTRAL GATEWAY ECU - NO. 9 CAN JUNCTION CONNECTOR)


    1. A000QJUE03
      Text in Illustration
      *a

      Front view of wire harness connector

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

      Disconnect the central gateway ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      N176-15 (CA5H) - N20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      N176-16 (CA5L) - N20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher

    OK

    REPLACE CENTRAL GATEWAY ECU Click here

    NG

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (CENTRAL GATEWAY ECU - NO. 9 CAN JUNCTION CONNECTOR)

  4. CONNECT CONNECTOR


    1. Reconnect the N131 No. 9 CAN junction connector.


    NEXT

  5. CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 4 CAN JUNCTION CONNECTOR)


    1. Disconnect the No. 4 CAN junction connector.

      A000SOPE02
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to No. 4 CAN Junction Connector)

      		 *b Front view of DLC3
      *c to Driving Support ECU Assembly (w/ Pre-crash Safety System) *d to No. 8 CAN Junction Connector
      *e to Absorber Control ECU (w/ Adaptive Variable Suspension System) *f to No. 9 CAN Junction Connector

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connect to
      N134-7 (CANH) - N20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Driving support ECU assembly*1
      N134-18 (CANL) - N20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      N134-8 (CANH) - N20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher No. 8 CAN junction connector
      N134-19 (CANL) - N20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      N134-9 (CANH) - N20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Absorber control ECU*2
      N134-20 (CANL) - N20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      N134-11 (CANH) - N20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher No. 9 CAN junction connector
      N134-22 (CANL) - N20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher

      • *1: w/ Pre-crash Safety System

      • *2: w/ Adaptive Variable Suspension System

      Result
      Result Proceed to
      OK A
      NG (No. 9 CAN junction connector CAN main wire) B
      NG (No. 8 CAN junction connector CAN main wire) C
      NG (ECU or sensor CAN branch wires) D

    A

    REPLACE NO. 4 CAN JUNCTION CONNECTOR

    B

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 4 CAN JUNCTION CONNECTOR - NO. 9 CAN JUNCTION CONNECTOR)

    D

    CHECK FOR SHORT TO GND IN CAN BUS WIRE (ECU, SENSOR) Click here

    C

  6. CONNECT CONNECTOR


    1. Reconnect the N134 No. 4 CAN junction connector.


    NEXT

  7. CHECK FOR SHORT TO GND IN CAN BUS WIRE (NO. 8 CAN JUNCTION CONNECTOR)

    A000N7OE02
    Text in Illustration
    *a

    Rear view of wire harness connector

    (to No. 8 CAN Junction Connector)

    		 *b Front view of DLC3
    *c to No. 4 CAN Junction Connector *d to Central Gateway ECU
    *e to Blind Spot Monitor Sensor RH (w/ Blind Spot Monitor System) - -

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connect to
      T46-7 (CANH) - N20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher No. 4 CAN junction connector
      T46-18 (CANL) - N20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      T46-9 (CANH) - N20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Central gateway ECU
      T46-20 (CANL) - N20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      T46-10 (CANH) - N20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Blind spot monitor sensor RH*
      T46-21 (CANL) - N20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher

      • *: w/ Blind Spot Monitor System

      Result
      Result Proceed to
      OK A
      NG (No. 4 CAN junction connector CAN main wire) B
      NG (Central gateway ECU CAN main wire) C
      NG (ECU or sensor CAN branch wires) D

    A

    REPLACE NO. 8 CAN JUNCTION CONNECTOR

    B

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 8 CAN JUNCTION CONNECTOR - NO. 4 CAN JUNCTION CONNECTOR)

    D

    CHECK FOR SHORT TO GND IN CAN BUS WIRE (ECU, SENSOR) Click here

    C

  8. CONNECT CONNECTOR


    1. Reconnect the T46 No. 8 CAN junction connector.


    NEXT

  9. CHECK FOR SHORT TO GND IN CAN BUS WIRE (CENTRAL GATEWAY ECU - NO. 8 CAN JUNCTION CONNECTOR)


    1. A000MXTE04
      Text in Illustration
      *a

      Front view of wire harness connector

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

      Disconnect the central gateway ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      N176-9 (CAXH) - N20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      N176-24 (CAXL) - N20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher

    OK

    REPLACE CENTRAL GATEWAY ECU Click here

    NG

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (CENTRAL GATEWAY ECU - NO. 8 CAN JUNCTION CONNECTOR)

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


    1. A000MT4E03
      Text in Illustration
      *a

      Component with harness connected

      (Central 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 bus line shorted to GND is connected.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      N176-15 (CA5H) - N20-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      N176-16 (CA5L) - N20-4 (CG) Cable disconnected from negative (-) auxiliary 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.


    OK

    REPLACE CORRESPONDING ECU OR SENSOR

    NG

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