CAN COMMUNICATION SYSTEM(for RHD) Check Bus 2 Lines for Short Circuit

DESCRIPTION

There may be a short circuit between the CAN main bus lines and/or CAN branch lines when the resistance between terminals 18 (CA4H) and 17 (CA4L) of the central gateway ECU (network gateway ECU) is below 54 Ω.

Symptom Trouble Area
Resistance between terminals 18 (CA4H) and 17 (CA4L) of the central gateway ECU (network gateway ECU) is below 54 Ω.

  • Short in CAN main bus lines

  • Short in CAN branch lines

  • Central gateway ECU (network gateway ECU)

  • Combination meter assembly

  • ECM

  • Power steering ECU assembly

  • Main body ECU (multiplex network body ECU)

  • Steering sensor

  • Airbag ECU assembly

  • Skid control ECU (brake actuator assembly)

  • Air conditioning amplifier assembly

  • Certification ECU (smart key ECU assembly)

  • Headlight ECU sub-assembly LH

  • Engine stop and start ECU

  • Parking brake ECU assembly

  • No. 4 CAN junction connector

  • No. 3 CAN junction connector

WIRING DIAGRAM

B006PU6E01
B006NYQE01

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

  • Before replacing the main body ECU (multiplex network body ECU), ECM or certification ECU (smart key ECU assembly), refer to Service Bulletin.

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 IN CAN BUS LINES (COMBINATION METER ASSEMBLY)


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

    2. Disconnect the G16 combination meter assembly connector.

    3. B006OUYC55
      *a

      Front view of wire harness connector

      (to Combination Meter Assembly)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G16-23 (CANH) - G16-22 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
      Result
      Result
      OK
      NG

    OK

    REPLACE COMBINATION METER ASSEMBLY Click here

    NG

  2. CHECK FOR SHORT IN CAN BUS LINES (ECM)


    1. Reconnect the G16 combination meter assembly connector.

    2. Disconnect the A53 ECM connector.

    3. B006MO7C93
      *a

      Front view of wire harness connector

      (to ECM)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A53-13 (CANH) - A53-26 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
      Result
      Result
      OK
      NG

    OK

    REPLACE ECM for 2AR-FE: Click here
    REPLACE ECM for 2GR-FKS: Click here

    NG

  3. CHECK FOR SHORT IN CAN BUS LINES (NO. 4 CAN JUNCTION CONNECTOR)


    1. Reconnect the A53 ECM connector.

    2. Disconnect the G98 No. 4 CAN junction connector.

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

      B006QVZC24
      *a

      Front view of wire harness connector

      (to No. 4 CAN Junction Connector)

      		 *b to No. 3 CAN Junction Connector
      *c to Combination Meter Assembly *d to Certification ECU (Smart Key ECU Assembly)
      *e to Power Steering ECU Assembly *f to Steering Sensor
      *g to Engine Stop and Start ECU *h to Central Gateway ECU (Network Gateway ECU)
      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      G98-1 (CANH) - G98-11 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω No. 3 CAN junction connector
      G98-2 (CANH) - G98-12 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Combination meter assembly
      G98-3 (CANH) - G98-13 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Certification ECU (smart key ECU assembly)
      G98-5 (CANH) - G98-15 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Power steering ECU assembly
      G98-7 (CANH) - G98-17 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Steering sensor
      G98-8 (CANH) - G98-18 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Engine stop and start ECU
      G98-10 (CANH) - G98-20 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Central gateway ECU (network gateway ECU)
      Result
      Result Proceed to
      OK A
      NG (Line to central gateway ECU (network gateway ECU)) B
      NG (Line to No. 3 CAN junction connector) C
      NG (Line to combination meter assembly) D
      NG (Line to ECU or sensor) E

    A

    REPLACE NO. 4 CAN JUNCTION CONNECTOR

    C

    CHECK FOR SHORT IN CAN BUS LINES (NO. 3 CAN JUNCTION CONNECTOR) Click here

    D

    REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 4 CAN JUNCTION CONNECTOR - COMBINATION METER ASSEMBLY)

    E

    GO TO STEP 6 Click here

    B

  4. CHECK FOR SHORT IN CAN BUS LINES (CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))


    1. Reconnect the G98 No. 4 CAN junction connector.

    2. Disconnect the G116 central gateway ECU (network gateway ECU) connector.

    3. B006QJGC91
      *a

      Front view of wire harness connector

      (to Central Gateway ECU (Network Gateway ECU))

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G116-18 (CA4H) - G116-17 (CA4L) Cable disconnected from negative (-) battery terminal 54 to 69 Ω
      Result
      Result
      OK
      NG

    OK

    REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) Click here

    NG

    REPAIR OR REPLACE CAN BRANCH LINES OR CONNECTOR (CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) - NO. 4 CAN JUNCTION CONNECTOR)

  5. CHECK FOR SHORT IN CAN BUS LINES (NO. 3 CAN JUNCTION CONNECTOR)


    1. Reconnect the G98 No. 4 CAN junction connector.

    2. Disconnect the G97 No. 3 CAN junction connector.

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

      B006QVZC25
      *a

      Front view of wire harness connector

      (to No. 3 CAN Junction Connector)

      		 *b to ECM
      *c to Main Body ECU (Multiplex Network Body ECU) *d to Airbag ECU Assembly
      *e to Parking Brake ECU Assembly *f to Skid Control ECU (Brake Actuator Assembly)
      *g to No. 4 CAN Junction Connector *h to Headlight ECU Sub-assembly LH
      *i to Air Conditioning Amplifier Assembly - -
      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      G97-3 (CANH) - G97-13 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω ECM
      G97-4 (CANH) - G97-14 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Main body ECU (multiplex network body ECU)
      G97-5 (CANH) - G97-15 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Airbag ECU assembly
      G97-6 (CANH) - G97-16 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Parking brake ECU assembly
      G97-7 (CANH) - G97-17 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Skid control ECU (brake actuator assembly)
      G97-8 (CANH) - G97-18 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω No. 4 CAN junction connector
      G97-9 (CANH) - G97-19 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Headlight ECU sub-assembly LH
      G97-10 (CANH) - G97-20 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Air conditioning amplifier assembly
      Result
      Result Proceed to
      OK A
      NG (Line to No. 4 CAN junction connector) B
      NG (Line to ECM) C
      NG (Line to ECU or sensor) D

    A

    REPLACE NO. 3 CAN JUNCTION CONNECTOR

    B

    REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 3 CAN JUNCTION CONNECTOR - NO. 4 CAN JUNCTION CONNECTOR)

    C

    REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 3 CAN JUNCTION CONNECTOR - ECM)

    D

  6. CHECK FOR SHORT IN CAN BUS LINES (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 short circuited branch line is connected.

      Click here

    3. B006LI0C28
      *a

      Component with harness connected

      (Central Gateway ECU (Network Gateway ECU))

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G116-18 (CA4H) - G116-17 (CA4L) Cable disconnected from negative (-) battery terminal 54 to 69 Ω

      Tech Tips


      • If the resistance becomes normal (between 54 and 69 Ω) 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 in the wire harness and repair or replace the wire harness or connector if necessary.

      Result
      Result
      OK
      NG

    OK

    REPLACE ECU OR SENSOR

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR