CAN COMMUNICATION SYSTEM Check Bus 3 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 6 (CA3H) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3, or terminal 21 (CA3L) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3.

Symptom Trouble Area

  • There is no resistance between terminal 6 (CA3H) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3, or terminal 21 (CA3L) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3.

  • There is no resistance between terminal 19 (CAYH) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3, or terminal 20 (CAYL) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3.

  • Short to GND in CAN main bus wire

  • Short to GND in CAN branch wire

  • Central gateway ECU (network gateway ECU)

  • Telematics transceiver*1

  • Bus buffer ECU*2

  • Radio receiver assembly*3

  • No. 10 CAN junction connector
*1: w/ Telematics Transceiver
*2: w/ Bus Buffer ECU
*3: w/ Audio and Visual System

WIRING DIAGRAM

B002JEZE08

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 power 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 (-) 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 negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary 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 power 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


  • 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. 10 CAN JUNCTION CONNECTOR)


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

    2. Disconnect the No. 10 CAN junction connector.

      B002JJ0C02
      *a

      Front view of wire harness connector

      (to No. 10 CAN Junction Connector)

      		 *b to Central Gateway ECU (Network Gateway ECU)
      *c to Radio Receiver Assembly (w/ Audio and Visual System) *d to Telematics Transceiver (w/ Telematics Transceiver)
      *e to Bus Buffer ECU (w/ Bus Buffer ECU) *f to Central Gateway ECU (Network Gateway ECU)
      *g Front view of DLC3 - -

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      I166-1 (CANH) - I7-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Central gateway ECU (network gateway ECU)
      I166-12 (CANL) - I7-4 (CG)
      I166-2 (CANH) - I7-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Radio receiver assembly*1
      I166-13 (CANL) - I7-4 (CG)
      I166-3 (CANH) - I7-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Telephone transceiver assembly*2
      I166-14 (CANL) - I7-4 (CG)
      I166-4 (CANH) - I7-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Bus buffer ECU*3
      I166-15 (CANL) - I7-4 (CG)
      I166-5 (CANH) - I7-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Central gateway ECU (network gateway ECU)
      I166-16 (CANL) - I7-4 (CG)
      *1: w/ Audio and Visual System
      *2: w/ Telematics Transceiver
      *3: w/ Bus Buffer ECU
      Result
      Result Proceed to
      OK A
      NG (Central gateway ECU [network gateway ECU] CAN main wire) B
      NG (Wire to ECU or sensor) C

    A

    REPLACE NO. 10 CAN JUNCTION CONNECTOR

    C

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

    B

  2. CONNECT CONNECTOR


    1. Reconnect the I166 No. 10 CAN junction connector.

      Result
      Proceed to
      NEXT

    NEXT

  3. CHECK FOR SHORT TO GND IN CAN BUS WIRE (CENTRAL GATEWAY ECU [NETWORK GATEWAY ECU] - NO. 10 CAN JUNCTION CONNECTOR)


    1. B002HF3C02
      *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
      I164-6 (CA3H) - I7-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      I164-21 (CA3L) - I7-4 (CG)
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) for LHD: Click here
    REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) for RHD: Click here

    NG

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (CENTRAL GATEWAY ECU [NETWORK GATEWAY ECU] - NO. 10 CAN JUNCTION CONNECTOR)

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


    1. B002IPVC50
      *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 GND is connected.

      Click here

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      I164-6 (CA3H) - I7-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      I164-21 (CA3L) - I7-4 (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
      Proceed to
      OK
      NG

    OK

    REPLACE ECU OR SENSOR

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR