CAN COMMUNICATION SYSTEM Check Bus 5 Line for Short to GND

DESCRIPTION

There may be a short circuit between one of the CAN bus lines and GND when there is no resistance 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
There is no resistance 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 ground in CAN main bus line

  • Short to ground in CAN branch line

  • Central gateway ECU (network gateway ECU)

  • Driving support ECU assembly

    (w/ Lexus Safety System +)

  • Absorber control ECU

    (w/ AVS System)

  • Clearance warning ECU assembly

    (w/ LEXUS Parking Assist-sensor System)

  • Forward recognition camera

    (w/ Lexus Safety System +)

  • Millimeter wave radar sensor assembly

    (w/ Lexus Safety System +)

  • Blind spot monitor sensor LH

    (w/ Blind Spot Monitor System)

  • Rear television camera assembly

    (w/ Parking Assist Monitor System)

  • No. 12 CAN junction connector

    (for LHD)

  • No. 14 CAN junction connector

    (for RHD)

  • No. 17 CAN junction connector

  • No. 19 CAN junction connector

    (for RHD)

  • No. 20 CAN junction connector

    (for LHD)

  • No. 2 CAN junction terminal

WIRING DIAGRAM

B0073M5E01
B00746ZE03
B0076ZME01
B00746ZE06

CAUTION / NOTICE / HINT

CAUTION:

When performing the confirmation driving pattern, obey all speed limits and traffic laws.

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 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.

    Click here

  • 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) and wait for 1 minute or more. Then operate the suspected malfunctioning system and drive the vehicle at 60 km/h (37 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.

    Click here

Tech Tips


  • Before disconnecting related connectors for inspection, push in on each connector body to check that the connector is not loose or disconnected.

  • When a connector is disconnected, check that the terminals and connector body are not cracked, deformed or corroded.

PROCEDURE


  1. CHECK VEHICLE TYPE


    1. Check vehicle type.

      Result
      Result Proceed to
      for LHD A
      for RHD B

    B
    A
  2. CHECK FOR SHORT TO GND IN CAN BUS LINE (NO. 20 CAN JUNCTION CONNECTOR)


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

    2. Disconnect the O198 No. 20 CAN junction connector.

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

      B0076IHC12
      *1 DLC3 - -
      *a

      Front view of wire harness connector

      (to No. 20 CAN Junction Connector)

      *b to No. 12 CAN Junction Connector
      *c

      to Forward Recognition Camera

      (w/ Lexus Safety System +)

      *d

      to Millimeter Wave Radar Sensor Assembly

      (w/ Lexus Safety System +)

      *e

      to Clearance Warning ECU Assembly

      (w/ LEXUS Parking Assist-sensor System)

      *f to No. 17 CAN Junction Connector
      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      O198-1 (CANH) - O8-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher No. 12 CAN junction connector
      O198-7 (CANL) - O8-4 (CG)
      O198-2 (CANH) - O8-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Forward recognition camera*1
      O198-8 (CANL) - O8-4 (CG)
      O198-3 (CANH) - O8-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Millimeter wave radar sensor assembly*1
      O198-9 (CANL) - O8-4 (CG)
      O198-5 (CANH) - O8-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Clearance warning ECU assembly*2
      O198-11 (CANL) - O8-4 (CG)
      O198-6 (CANH) - O8-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher No. 17 CAN junction connector
      O198-12 (CANL) - O8-4 (CG)

      • *1: w/ Lexus Safety System +

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

      Result
      Result Proceed to
      OK A
      NG (Line to No. 12 CAN junction connector) B
      NG (Line to No. 17 CAN junction connector) C
      NG (Line to ECU or sensor) D

    A
    C
    D
    B
  3. CHECK FOR SHORT TO GND IN CAN BUS LINE (NO. 12 CAN JUNCTION CONNECTOR)


    1. Disconnect the O171, O172, O173 and O174 No. 12 CAN junction connectors.

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

      B0074IUC08
      *1 DLC3 - -
      *a

      Rear view of wire harness connector

      (to No. 12 CAN Junction Connector)

      *b to Central Gateway ECU (Network Gateway ECU)
      *c to No. 20 CAN Junction Connector *d

      to Absorber Control ECU

      (w/ AVS System)

      *e

      to Driving Support ECU Assembly

      (w/ Lexus Safety System +)

      - -
      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      O171-1 (CANH) - O8-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Central gateway ECU (network gateway ECU)
      O171-2 (CANL) - O8-4 (CG)
      O172-1 (CANH) - O8-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher No. 20 CAN junction connector
      O172-2 (CANL) - O8-4 (CG)
      O173-1 (CANH) - O8-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Absorber control ECU*1
      O173-2 (CANL) - O8-4 (CG)
      O174-1 (CANH) - O8-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Driving support ECU assembly*2
      O174-2 (CANL) - O8-4 (CG)

      • *1: w/ AVS System

      • *2: w/ Lexus Safety System +

      Result
      Result Proceed to
      OK A
      NG (Line to central gateway ECU (network gateway ECU)) B
      NG (Line to No. 20 CAN junction connector) C
      NG (Line to ECU or sensor) D

    A
    C
    D
    B
  4. CHECK FOR SHORT TO GND IN CAN BUS LINE (CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))


    1. Disconnect the O157 central gateway ECU (network gateway ECU) connector.

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

      B00756YC14
      *1 DLC3 - -
      *a

      Front view of wire harness connector

      (to Central Gateway ECU (Network Gateway ECU))

      - -
      Standard Resistance
      Tester Connection Condition Specified Condition
      O157-15 (CA5H) - O8-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      O157-16 (CA5L) - O8-4 (CG)
      Result
      Result
      OK
      NG

    OK
    NG
  5. CHECK FOR SHORT TO GND IN CAN BUS LINE (NO. 17 CAN JUNCTION CONNECTOR)


    1. Disconnect the U60 No. 17 CAN junction connector.

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

      B0076IHC04
      *1 DLC3 - -
      *a

      Front view of wire harness connector

      (to No. 17 CAN Junction Connector)

      *b

      to Rear Television Camera Assembly

      (w/ Parking Assist Monitor System)

      *c to No. 20 CAN Junction Connector *d to No. 2 CAN Junction Terminal
      *e

      to Blind Spot Monitor Sensor LH

      (w/ Blind Spot Monitor System)

      - -
      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      U60-2 (CANH) - O8-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Rear television camera assembly*1
      U60-8 (CANL) - O8-4 (CG)
      U60-3 (CANH) - O8-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher No. 20 CAN junction connector
      U60-9 (CANL) - O8-4 (CG)
      U60-4 (CANH) - O8-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher No. 2 CAN junction terminal
      U60-10 (CANL) - O8-4 (CG)
      U60-5 (CANH) - O8-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Blind spot monitor sensor LH*2
      U60-11 (CANL) - O8-4 (CG)

      • *1: w/ Parking Assist Monitor System

      • *2: w/ Blind Spot Monitor System

      Result
      Result Proceed to
      OK A
      NG (Line to No. 20 CAN junction connector) B
      NG (Line to No. 2 CAN junction terminal) C
      NG (Line to ECU or sensor) D

    A
    B
    D
    C
  6. CHECK FOR SHORT TO GND IN CAN BUS LINE (NO. 2 CAN JUNCTION TERMINAL)


    1. Disconnect the O102 No. 2 CAN junction terminal connector.

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

      B0072N0C04
      *1 DLC3 - -
      *a

      Front view of wire harness connector

      (to No. 2 CAN Junction Terminal)

      - -
      Standard Resistance
      Tester Connection Condition Specified Condition
      O102-3 (CANH) - O8-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      O102-2 (CANL) - O8-4 (CG)
      Result
      Result
      OK
      NG

    OK
    NG
  7. CHECK FOR SHORT TO GND IN CAN BUS LINE (ECU OR SENSOR)


    1. Reconnect all wire harness connectors.

    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.

      Click here

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

      B007487C22
      *1 DLC3 - -
      *a

      Component with harness connected

      (Central Gateway ECU (Network Gateway ECU))

      - -
      Standard Resistance
      Tester Connection Condition Specified Condition
      O157-15 (CA5H) - O8-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      O157-16 (CA5L) - O8-4 (CG)

      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.

      • If the resistance does not become normal when the connector is disconnected from the ECU or sensor, check for a short to ground in the wire harness and repair or replace the wire harness or connector if necessary.

      Result
      Result
      OK
      NG

    OK
    NG
  8. CHECK FOR SHORT TO GND IN CAN BUS LINE (NO. 14 CAN JUNCTION CONNECTOR)


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

    2. Disconnect the O180, O181, O182, O183 and O184 No. 14 CAN junction connectors.

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

      B0077BFC06
      *1 DLC3 - -
      *a

      Rear view of wire harness connector

      (to No. 14 CAN Junction Connector)

      *b to No. 19 CAN Junction Connector
      *c

      to Forward Recognition Camera

      (w/ Lexus Safety System +)

      *d

      to Millimeter Wave Radar Sensor Assembly

      (w/ Lexus Safety System +)

      *e

      to Clearance Warning ECU Assembly

      (w/ LEXUS Parking Assist-sensor System)

      *f to No. 17 CAN Junction Connector
      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      O180-1 (CANH) - O8-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher No. 19 CAN junction connector
      O180-2 (CANL) - O8-4 (CG)
      O181-1 (CANH) - O8-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Forward recognition camera*1
      O181-2 (CANL) - O8-4 (CG)
      O182-1 (CANH) - O8-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Millimeter wave radar sensor assembly*1
      O182-2 (CANL) - O8-4 (CG)
      O183-1 (CANH) - O8-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Clearance warning ECU assembly*2
      O183-2 (CANL) - O8-4 (CG)
      O184-1 (CANH) - O8-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher No. 17 CAN junction connector
      O184-2 (CANL) - O8-4 (CG)

      • *1: w/ Lexus Safety System +

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

      Result
      Result Proceed to
      OK A
      NG (Line to No. 19 CAN junction connector) B
      NG (Line to No. 17 CAN junction connector) C
      NG (Line to ECU or sensor) D

    A
    C
    D
    B
  9. CHECK FOR SHORT TO GND IN CAN BUS LINE (NO. 19 CAN JUNCTION CONNECTOR)


    1. Disconnect the O197 No. 19 CAN junction connector.

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

      B0076IHC14
      *1 DLC3 - -
      *a

      Front view of wire harness connector

      (to No. 19 CAN Junction Connector)

      *b

      to Absorber Control ECU

      (w/ AVS System)

      *c

      to Driving Support ECU Assembly

      (w/ Lexus Safety System +)

      *d to Central Gateway ECU (Network Gateway ECU)
      *e to No. 14 CAN Junction Connector - -
      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      O197-1 (CANH) - O8-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Absorber control ECU*1
      O197-7 (CANL) - O8-4 (CG)
      O197-2 (CANH) - O8-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Driving support ECU assembly*2
      O197-8 (CANL) - O8-4 (CG)
      O197-3 (CANH) - O8-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Central gateway ECU (network gateway ECU)
      O197-9 (CANL) - O8-4 (CG)
      O197-4 (CANH) - O8-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher No. 14 CAN junction connector
      O197-10 (CANL) - O8-4 (CG)

      • *1: w/ AVS System

      • *2: w/ Lexus Safety System +

      Result
      Result Proceed to
      OK A
      NG (Line to central gateway ECU (network gateway ECU)) B
      NG (Line to No. 14 CAN junction connector) C
      NG (Line to ECU or sensor) D

    A
    C
    D
    B
  10. CHECK FOR SHORT TO GND IN CAN BUS LINE (CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))


    1. Disconnect the O157 central gateway ECU (network gateway ECU) connector.

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

      B00756YC14
      *1 DLC3 - -
      *a

      Front view of wire harness connector

      (to Central Gateway ECU (Network Gateway ECU))

      - -
      Standard Resistance
      Tester Connection Condition Specified Condition
      O157-15 (CA5H) - O8-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      O157-16 (CA5L) - O8-4 (CG)
      Result
      Result
      OK
      NG

    OK
    NG
  11. CHECK FOR SHORT TO GND IN CAN BUS LINE (NO. 17 CAN JUNCTION CONNECTOR)


    1. Disconnect the U60 No. 17 CAN junction connector.

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

      B0076IHC04
      *1 DLC3 - -
      *a

      Front view of wire harness connector

      (to No. 17 CAN Junction Connector)

      *b

      to Rear Television Camera Assembly

      (w/ Parking Assist Monitor System)

      *c to No. 14 CAN Junction Connector *d to No. 2 CAN Junction Terminal
      *e

      to Blind Spot Monitor Sensor LH

      (w/ Blind Spot Monitor System)

      - -
      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      U60-2 (CANH) - O8-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Rear television camera assembly*1
      U60-8 (CANL) - O8-4 (CG)
      U60-3 (CANH) - O8-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher No. 14 CAN junction connector
      U60-9 (CANL) - O8-4 (CG)
      U60-4 (CANH) - O8-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher No. 2 CAN junction terminal
      U60-10 (CANL) - O8-4 (CG)
      U60-5 (CANH) - O8-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Blind spot monitor sensor LH*2
      U60-11 (CANL) - O8-4 (CG)

      • *1: w/ Parking Assist Monitor System

      • *2: w/ Blind Spot Monitor System

      Result
      Result Proceed to
      OK A
      NG (Line to No. 14 CAN junction connector) B
      NG (Line to No. 2 CAN junction terminal) C
      NG (Line to ECU or sensor) D

    A
    B
    D
    C
  12. CHECK FOR SHORT TO GND IN CAN BUS LINE (NO. 2 CAN JUNCTION TERMINAL)


    1. Disconnect the O102 No. 2 CAN junction terminal connector.

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

      B0072N0C04
      *1 DLC3 - -
      *a

      Front view of wire harness connector

      (to No. 2 CAN Junction Terminal)

      - -
      Standard Resistance
      Tester Connection Condition Specified Condition
      O102-3 (CANH) - O8-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      O102-2 (CANL) - O8-4 (CG)
      Result
      Result
      OK
      NG

    OK
    NG
  13. CHECK FOR SHORT TO GND IN CAN BUS LINE (ECU OR SENSOR)


    1. Reconnect all wire harness connectors.

    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.

      Click here

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

      B007487C22
      *1 DLC3 - -
      *a

      Component with harness connected

      (Central Gateway ECU (Network Gateway ECU))

      - -
      Standard Resistance
      Tester Connection Condition Specified Condition
      O157-15 (CA5H) - O8-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      O157-16 (CA5L) - O8-4 (CG)

      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.

      • If the resistance does not become normal when the connector is disconnected from the ECU or sensor, check for a short to ground in the wire harness and repair or replace the wire harness or connector if necessary.

      Result
      Result
      OK
      NG

    OK
    NG