CAN COMMUNICATION SYSTEM 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)

  • Front steering control ECU

    (w/ VGRS system)

  • Yaw rate sensor

  • Headlight leveling ECU assembly

    (for Single Beam Headlight)

  • Engine stop and start ECU

    (w/ Stop and Start System)

  • Stereo component equalizer assembly

    (w/ ASC System)

  • No. 1 CAN junction connector

  • No. 2 CAN junction connector

WIRING DIAGRAM

B0075MPE01
B0074WVE03
B0074Y8E01
B0075OEE03

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 (ECM)


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

    2. Disconnect the A91 or A96 ECM connector.

    3. B00750PC11
      *A for 8AR-FTS
      *B for 2GR-FKS
      *a

      Front view of wire harness connector

      (to ECM)

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

      Standard Resistance
      for 8AR-FTS
      Tester Connection Condition Specified Condition
      A91-13 (CANH) - A91-26 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
      for 2GR-FKS
      Tester Connection Condition Specified Condition
      A96-13 (CANH) - A96-26 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
      Result
      Result Proceed to
      OK (for 8AR-FTS) A
      OK (for 2GR-FKS) B
      NG C

    A

    REPLACE ECM Click here

    B

    REPLACE ECM Click here

    C

  2. CHECK FOR SHORT IN CAN BUS LINES (COMBINATION METER ASSEMBLY)


    1. Reconnect the A91 or A96 ECM connector.

    2. Disconnect the O3 combination meter assembly connector.

    3. B0075BHC08
      *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
      O3-29 (CANH) - O3-30 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω
      Result
      Result Proceed to
      OK A
      NG (for LHD) B
      NG (for RHD) C

    A

    REPLACE COMBINATION METER ASSEMBLY Click here

    C

    CHECK FOR SHORT IN CAN BUS LINES (NO. 2 CAN JUNCTION CONNECTOR) Click here

    B

  3. CHECK FOR SHORT IN CAN BUS LINES (NO. 1 CAN JUNCTION CONNECTOR)


    1. Reconnect the O3 combination meter assembly connector.

    2. Disconnect the O104 No. 1 CAN junction connector.

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

      B0072MOC16
      *a

      Front view of wire harness connector

      (to No. 1 CAN Junction Connector)

      		 *b to No. 2 CAN Junction Connector
      *c to Combination Meter Assembly *d to Central Gateway ECU (Network Gateway ECU)
      *e to Air Conditioning Amplifier Assembly *f to Certification ECU (Smart Key ECU Assembly)
      *g

      to Stereo Component Equalizer Assembly

      (w/ ASC System)

      		 *h to Power Steering ECU Assembly
      *i

      to Front Steering Control ECU

      (w/ VGRS System)

      		 *j

      Engine Stop and Start ECU

      (w/ Stop and Start System)
      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      O104-1 (CANH) - O104-11 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω No. 2 CAN junction connector
      O104-2 (CANH) - O104-12 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Combination meter assembly
      O104-4 (CANH) - O104-14 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Central gateway ECU (network gateway ECU)
      O104-5 (CANH) - O104-15 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Air conditioning amplifier assembly
      O104-7 (CANH) - O104-17 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Certification ECU (smart key ECU assembly)
      O104-8 (CANH) - O104-18 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Stereo component equalizer assembly*1
      O104-9 (CANH) - O104-19 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Power steering ECU assembly
      O104-10 (CANH) - O104-20 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Front steering control ECU*2
      O104-10 (CANH) - O104-20 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Engine stop and start ECU*3

      • *1: w/ ASC System

      • *2: w/ VGRS System

      • *3: w/ Stop and Start System

      Result
      Result Proceed to
      OK A
      NG (Line to central gateway ECU (network gateway ECU)) B
      NG (Line to No. 2 CAN junction connector) C
      NG (Line to combination meter assembly) D
      NG (Line to ECU or sensor) E

    A

    REPLACE NO. 1 CAN JUNCTION CONNECTOR

    C

    CHECK FOR SHORT IN CAN BUS LINES (NO. 2 CAN JUNCTION CONNECTOR) Click here

    D

    REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 1 CAN JUNCTION CONNECTOR - COMBINATION METER ASSEMBLY)

    E

    GO TO STEP 9 Click here

    B

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


    1. Reconnect the O104 No. 1 CAN junction connector.

    2. Disconnect the O157 central gateway ECU (network gateway ECU) connector.

    3. B0075Q1C20
      *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
      O157-18 (CA4H) - O157-17 (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. 1 CAN JUNCTION CONNECTOR)

  5. CHECK FOR SHORT IN CAN BUS LINES (NO. 2 CAN JUNCTION CONNECTOR)


    1. Reconnect the O104 No. 1 CAN junction connector.

    2. Disconnect the O105 No. 2 CAN junction connector.

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

      B0072MOC10
      *a

      Front view of wire harness connector

      (to No. 2 CAN Junction Connector)

      		 *b to No. 1 CAN Junction Connector
      *c to Main Body ECU (Multiplex Network Body ECU) *d to ECM
      *e

      to Headlight Leveling ECU Assembly

      (for Single Beam Headlight)

      		 *f to Airbag ECU Assembly
      *g to Yaw Rate Sensor *h to Steering Sensor
      *i to Skid Control ECU (Brake Actuator Assembly) - -
      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      O105-1 (CANH) - O105-11 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω No. 1 CAN junction connector
      O105-2 (CANH) - O105-12 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Main body ECU (multiplex network body ECU)
      O105-3 (CANH) - O105-13 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω ECM
      O105-4 (CANH) - O105-14 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Headlight leveling ECU assembly*
      O105-5 (CANH) - O105-15 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Airbag ECU assembly
      O105-6 (CANH) - O105-16 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Yaw rate sensor
      O105-9 (CANH) - O105-19 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Steering sensor
      O105-10 (CANH) - O105-20 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Skid control ECU (brake actuator assembly)

      • *: for Single Beam Headlight

      Result
      Result Proceed to
      OK A
      NG (Line to No. 1 CAN junction connector) B
      NG (Line to ECM) C
      NG (Line to ECU or sensor) D

    A

    REPLACE NO. 2 CAN JUNCTION CONNECTOR

    B

    REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 2 CAN JUNCTION CONNECTOR - NO. 1 CAN JUNCTION CONNECTOR)

    C

    REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 2 CAN JUNCTION CONNECTOR - ECM)

    D

    GO TO STEP 9 Click here

  6. CHECK FOR SHORT IN CAN BUS LINES (NO. 2 CAN JUNCTION CONNECTOR)


    1. Reconnect the O3 combination meter assembly connector.

    2. Disconnect the O105 No. 2 CAN junction connector.

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

      B0072MOC18
      *a

      Front view of wire harness connector

      (to No. 2 CAN Junction Connector)

      		 *b to No. 1 CAN Junction Connector
      *c to Main Body ECU (Multiplex Network Body ECU) *d to ECM
      *e

      to Headlight Leveling ECU Assembly

      (for Single Beam Headlight)

      		 *f to Central Gateway ECU (Network Gateway ECU)
      *g to Air Conditioning Amplifier Assembly *h

      to Front Steering Control ECU

      (w/ VGRS System)
      *i

      Engine Stop and Start ECU

      (w/ Stop and Start System)

      		 *j to Certification ECU (Smart Key ECU Assembly)
      *k to Power Steering ECU Assembly - -
      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      O105-1 (CANH) - O105-11 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω No. 1 CAN junction connector
      O105-2 (CANH) - O105-12 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Main body ECU (multiplex network body ECU)
      O105-3 (CANH) - O105-13 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω ECM
      O105-4 (CANH) - O105-14 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Headlight leveling ECU assembly*1
      O105-5 (CANH) - O105-15 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Central gateway ECU (network gateway ECU)
      O105-6 (CANH) - O105-16 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Air conditioning amplifier assembly
      O105-7 (CANH) - O105-17 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Front steering control ECU*2
      O105-7 (CANH) - O105-17 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Engine stop and start ECU*3
      O105-8 (CANH) - O105-18 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Certification ECU (smart key ECU assembly)
      O105-10 (CANH) - O105-20 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Power steering ECU assembly

      • *1: for Single Beam Headlight

      • *2: w/ VGRS System

      • *3: w/ Stop and Start System

      Result
      Result Proceed to
      OK A
      NG (Line to central gateway ECU (network gateway ECU)) B
      NG (Line to No. 1 CAN junction connector) C
      NG (Line to ECM) D
      NG (Line to ECU or sensor) E

    A

    REPLACE NO. 2 CAN JUNCTION CONNECTOR

    C

    CHECK FOR SHORT IN CAN BUS LINES (NO. 1 CAN JUNCTION CONNECTOR) Click here

    D

    REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 2 CAN JUNCTION CONNECTOR - ECM)

    E

    GO TO STEP 9 Click here

    B

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


    1. Reconnect the O105 No. 2 CAN junction connector.

    2. Disconnect the O157 central gateway ECU (network gateway ECU) connector.

    3. B0075Q1C20
      *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
      O157-18 (CA4H) - O157-17 (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. 2 CAN JUNCTION CONNECTOR)

  8. CHECK FOR SHORT IN CAN BUS LINES (NO. 1 CAN JUNCTION CONNECTOR)


    1. Reconnect the O105 No. 2 CAN junction connector.

    2. Disconnect the O104 No. 1 CAN junction connector.

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

      B0072MOC19
      *a

      Front view of wire harness connector

      (to No. 1 CAN Junction Connector)

      		 *b to No. 2 CAN Junction Connector
      *c to Combination Meter Assembly *d to Airbag ECU Assembly
      *e to Yaw Rate Sensor *f to Skid Control ECU (Brake Actuator Assembly)
      *g to Steering Sensor *h

      to Stereo Component Equalizer Assembly

      (w/ ASC System)
      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      O104-1 (CANH) - O104-11 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω No. 2 CAN junction connector
      O104-2 (CANH) - O104-12 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Combination meter assembly
      O104-4 (CANH) - O104-14 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Airbag ECU assembly
      O104-5 (CANH) - O104-15 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Yaw rate sensor
      O104-6 (CANH) - O104-16 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Skid control ECU (brake actuator assembly)
      O104-7 (CANH) - O104-17 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Steering sensor
      O104-9 (CANH) - O104-19 (CANL) Cable disconnected from negative (-) battery terminal 200 Ω or higher Stereo component equalizer assembly*

      • *: w/ ASC System

      Result
      Result Proceed to
      OK A
      NG (Line to No. 2 CAN junction connector) B
      NG (Line to combination meter assembly) C
      NG (Line to ECU or sensor) D

    A

    REPLACE NO. 1 CAN JUNCTION CONNECTOR

    B

    REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 1 CAN JUNCTION CONNECTOR - NO. 2 CAN JUNCTION CONNECTOR)

    C

    REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 1 CAN JUNCTION CONNECTOR - COMBINATION METER ASSEMBLY)

    D

  9. 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. B0073PAC12
      *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
      O157-18 (CA4H) - O157-17 (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