CAN COMMUNICATION SYSTEM(for LHD) 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 no resistance exists between terminal 6 (CA3H) of the central gateway ECU and terminal 16 (BAT) of the DLC3, or terminal 21 (CA3L) of the central gateway ECU and terminal 16 (BAT) of the DLC3.

Detection Item Trouble Area
No resistance exists between terminal 6 (CA3H) of the central gateway ECU and terminal 16 (BAT) of the DLC3, or terminal 21 (CA3L) of the central gateway ECU and terminal 16 (BAT) of the DLC3.

  • Short to +B in bus 3 CAN main wires

  • Short to +B in bus 3 CAN branch wires

  • Central gateway ECU

  • Multi-media module receiver assembly

  • Telematics transceiver*

  • No. 4 CAN junction connector

WIRING DIAGRAM

B002BR5E07

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, 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.

  • 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.

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


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

      B002C4AE01
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to No. 4 CAN Junction Connector)

      		 *b Front view of DLC3
      *c to Central Gateway ECU *d to Telematics Transceiver (w/ Telematics Transceiver)
      *e to Multi-media Module Receiver Assembly - -

    2. 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 Connect to
      N184-1 (CANH) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Central gateway ECU
      N184-12 (CANL) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      N184-2 (CANH) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Central gateway ECU
      N184-13 (CANL) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      N184-3 (CANH) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Telematics transceiver*
      N184-14 (CANL) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      N184-4 (CANH) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher Multi-media module receiver assembly
      N184-15 (CANL) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher

      • *: w/ Telematics Transceiver

      Result
      Result Proceed to
      OK A
      NG (Central gateway ECU CAN main wire) B
      NG (ECU or sensor CAN branch wires) C

    A

    REPLACE NO. 4 CAN JUNCTION CONNECTOR

    C

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

    B

  2. CONNECT CONNECTOR


    1. Reconnect the N184 No. 4 CAN junction connector.


    NEXT

  3. CHECK FOR SHORT TO B+ IN CAN BUS WIRE (CENTRAL GATEWAY ECU - NO. 4 CAN JUNCTION CONNECTOR)


    1. B002BCHE01
      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
      N176-6 (CA3H) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      N176-21 (CA3L) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      N176-19 (CAYH) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      N176-20 (CAYL) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher

    OK

    REPLACE CENTRAL GATEWAY ECU Click here

    NG

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (CENTRAL GATEWAY ECU - NO. 4 CAN JUNCTION CONNECTOR)

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


    1. B002BSGE02
      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 +B is connected

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      N176-6 (CA3H) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary battery terminal 6 kΩ or higher
      N176-21 (CA3L) - N20-16 (BAT) Cable disconnected from negative (-) auxiliary 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.


    OK

    REPLACE CORRESPONDING ECU OR SENSOR

    NG

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