CAN COMMUNICATION SYSTEM Check Bus 3 Line for Short to +B

DESCRIPTION

There may be a short circuit between one of the CAN bus lines and +B when there is no resistance between terminal 6 (CA3H) of the central gateway ECU (network gateway ECU) and terminal 16 (BAT) of the DLC3, or terminal 21 (CA3L) of the central gateway ECU (network gateway ECU) and terminal 16 (BAT) of the DLC3.

Symptom Trouble Area
There is no resistance between terminal 6 (CA3H) of the central gateway ECU (network gateway ECU) and terminal 16 (BAT) of the DLC3, or terminal 21 (CA3L) of the central gateway ECU (network gateway ECU) and terminal 16 (BAT) of the DLC3.
  • Short to +B in CAN main bus wire

  • Short to +B in CAN branch wire

  • Central gateway ECU (network gateway ECU)

  • Telephone transceiver assembly*1

  • Bus buffer ECU*2

  • Radio receiver assembly

  • Stereo component equalizer assembly

  • No. 5 CAN junction terminal

  • No. 4 CAN junction connector

  • No. 14 CAN junction connector

*1: w/ Telematics Transceiver
*2: w/ Bus Buffer ECU

WIRING DIAGRAM

B000VGEE02
B000VRXE05
*a No. 4 CAN Junction Connector
*b No. 14 CAN Junction Connector
*c Stereo Component Equalizer Assembly
*d No. 5 CAN Junction Terminal

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

  • Some parts must be initialized and set when replacing or removing and installing parts.

    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

  • The following malfunctions may occur if a radio receiver assembly from another vehicle is installed to this vehicle. Therefore, when replacing the radio receiver assembly, be sure to replace it with new one.


    • Communication malfunction DTC is output

    • Does not operate normally

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 FOR SHORT TO B+ IN CAN BUS WIRE (NO. 4 CAN JUNCTION CONNECTOR)


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

    2. B000YX3C21
      *a

      Front view of wire harness connector

      (to No. 4 CAN Junction Connector)

      *b Front view of DLC3
      *c to No. 14 CAN Junction Connector
      *d to Central Gateway ECU (Network Gateway ECU)
      *e to Telephone Transceiver Assembly (w/ Telematics Transceiver)
      *f to Radio Receiver Assembly
      *g to Bus Buffer ECU (w/ Bus Buffer ECU)

      Disconnect the No. 4 CAN junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      P116-7 (CANH) - P12-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher No. 14 CAN junction connector
      P116-18 (CANL) - P12-16 (BAT)
      P116-8 (CANH) - P12-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Central gateway ECU (network gateway ECU)
      P116-19 (CANL) - P12-16 (BAT)
      P116-9 (CANH) - P12-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Telephone transceiver assembly*1
      P116-20 (CANL) - P12-16 (BAT)
      P116-10 (CANH) - P12-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Radio receiver assembly
      P116-21 (CANL) - P12-16 (BAT)
      P116-11 (CANH) - P12-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Bus buffer ECU*2
      P116-22 (CANL) - P12-16 (BAT)
      *1: w/ Telematics Transceiver
      *2: w/ Bus Buffer ECU
      Result
      Result Proceed to
      OK A
      NG (Central gateway ECU [network gateway ECU] CAN main wire) B
      NG (No. 14 CAN junction connector CAN main wire) C
      NG (Wire to ECU or sensor) D

    A
    C
    D
    B
  2. CONNECT CONNECTOR


    1. Reconnect the P116 No. 4 CAN junction connector.

      Result
      Proceed to
      NEXT

    NEXT
  3. CHECK FOR SHORT TO B+ IN CAN BUS WIRE (CENTRAL GATEWAY ECU [NETWORK GATEWAY ECU])


    1. B000W88C62
      *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.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      P59-6 (CA3H) - P12-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher
      P59-21 (CA3L) - P12-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher
      Result
      Result
      OK
      NG

    OK
    NG
  4. CONNECT CONNECTOR


    1. Reconnect the P116 No. 4 CAN junction connector.

      Result
      Proceed to
      NEXT

    NEXT
  5. CHECK FOR SHORT TO B+ IN CAN BUS WIRE (NO. 14 CAN JUNCTION CONNECTOR)


    1. B000WKZC13
      *a

      Front view of wire harness connector

      No. 14 CAN Junction Connector

      *b Front view of DLC3
      *c to No. 5 CAN Junction Terminal
      *d to No. 4 CAN Junction Connector
      *e to Stereo Component Equalizer Assembly

      Disconnect the No. 14 CAN junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      X109-9 (CANH) - P12-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher No. 5 CAN junction terminal
      X109-20 (CANL) - P12-16 (BAT)
      X109-10 (CANH) - P12-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher No. 4 CAN junction connector
      X109-21 (CANL) - P12-16 (BAT)
      X109-11 (CANH) - P12-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher Stereo component equalizer assembly
      X109-22 (CANL) - P12-16 (BAT)
      Result
      Result Proceed to
      OK A
      NG (No. 4 CAN junction connector CAN main wire) B
      NG (Wire to ECU or sensor) C

    A
    B
    C
  6. CHECK FOR SHORT TO B+ IN CAN BUS WIRE (ECU, SENSOR)


    1. B000XBXC09
      *a

      Component with harness connected

      (Central Gateway ECU [Network Gateway ECU])

      *b Front view of DLC3

      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 +B is connected.

      Click here

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      P59-6 (CA3H) - P12-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher
      P59-21 (CA3L) - P12-16 (BAT) Cable disconnected from negative (-) battery terminal 6 kΩ or higher

      Tech Tips


      • If the resistance changes to 6 kΩ 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 +B in the wire harness and repair or replace the wire harness or connector if necessary.

      Result
      Result
      OK
      NG

    OK
    NG