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
No resistance exists 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.

  • Short to ground in CAN main bus line

  • Short to ground in CAN branch line

  • Central gateway ECU (network gateway ECU)

  • Navigation receiver assembly

    (for Navigation Receiver Type)

  • Radio and display receiver assembly

    (for Radio and Display Type)

  • Telematics transceiver

    (w/ Telematics Transceiver)

  • No. 7 CAN junction connector

WIRING DIAGRAM

A002BI3E08

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 ignition 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 ignition 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 ignition switch to ON and wait at least 31 seconds.

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

    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 FOR SHORT TO GND IN CAN BUS LINE (NO. 7 CAN JUNCTION CONNECTOR)


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

    2. Disconnect the F135 No. 7 CAN junction connector.

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

      A002B7TC08
      *1 DLC3 - -
      *a

      Front view of wire harness connector

      (to No. 7 CAN Junction Connector)

      		 *b to Central Gateway ECU (Network Gateway ECU)
      *c

      to Telematics Transceiver

      (w/ Telematics Transceiver)

      		 *d

      to Navigation Receiver Assembly

      (for Navigation Receiver Type)
      *e

      to Radio and Display Receiver Assembly

      (for Radio and Display Type)

      		 - -
      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      F135-1 (CANH) - F25-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Central gateway ECU (network gateway ECU)
      F135-12 (CANL) - F25-4 (CG)
      F135-2 (CANH) - F25-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Central gateway ECU (network gateway ECU)
      F135-13 (CANL) - F25-4 (CG)
      F135-4 (CANH) - F25-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Telematics transceiver*1
      F135-15 (CANL) - F25-4 (CG)
      F135-5 (CANH) - F25-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Navigation receiver assembly*2
      F135-16 (CANL) - F25-4 (CG)
      F135-5 (CANH) - F25-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher Radio and display receiver assembly*3
      F135-16 (CANL) - F25-4 (CG)

      • *1: w/ Telematics Transceiver

      • *2: for Navigation Receiver Type

      • *3: for Radio and Display Type

      Tech Tips

      If there is a short to ground in a CAN bus line without any CAN compatible optional devices connected to the option connector, repair or replace the CAN bus branch line or the option connector.

      Result
      Result Proceed to
      OK A
      NG (Central gateway ECU (network gateway ECU) main line) B
      NG (ECU or sensor branch line) C

    A

    REPLACE NO. 7 CAN JUNCTION CONNECTOR

    C

    CHECK FOR SHORT TO GND IN CAN BUS LINE (ECU OR SENSOR) Click here

    B

  2. CHECK FOR SHORT TO GND IN CAN BUS LINE (NO. 7 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))


    1. Disconnect the F127 central gateway ECU (network gateway ECU) connector.

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

      A002B7TC09
      *1 DLC3 - -
      *a

      Front view of wire harness connector

      (to No. 7 CAN Junction Connector)

      		 *b to Central Gateway ECU (Network Gateway ECU)
      Standard Resistance
      Tester Connection Condition Specified Condition
      F135-1 (CANH) - F25-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      F135-12 (CANL) - F25-4 (CG)
      F135-2 (CANH) - F25-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      F135-13 (CANL) - F25-4 (CG)
      Result
      Result
      OK
      NG

    OK

    REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) Click here

    NG

    REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (NO. 7 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))

  3. 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.

      A002CN9C96
      *1 DLC3 - -
      *a

      Component with harness connected

      (Central Gateway ECU (Network Gateway ECU))

      		 - -
      Standard Resistance
      Tester Connection Condition Specified Condition
      F127-6 (CA3H) - F25-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      F127-21 (CA3L) - F25-4 (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

    REPLACE CORRESPONDING ECU OR SENSOR

    NG

    REPAIR OR REPLACE CORRESPONDING ECU OR SENSOR BRANCH LINE OR CONNECTOR