CAN COMMUNICATION SYSTEM Check Bus 2 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 18 (CA4H) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3, or terminal 17 (CA4L) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3.

Symptom Trouble Area
No resistance exists between terminal 18 (CA4H) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3, or terminal 17 (CA4L) 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)

  • ECM

  • Combination meter assembly

  • Power steering ECU assembly

  • Main body ECU (multiplex network body ECU)

  • Steering sensor

  • Airbag sensor assembly

  • Skid control ECU assembly

  • Air conditioning amplifier assembly

  • Certification ECU (smart key ECU assembly)

  • Stereo component equalizer assembly

    (w/ ASC System)

  • Yaw rate sensor

  • Hybrid vehicle control ECU assembly

  • No. 1 CAN junction connector

  • No. 2 CAN junction connector

WIRING DIAGRAM

Figure 1. for LHD

B003YGBE01
B003Y6VE01

Figure 2. for RHD

B003XU5E01
B003Y4GE01

CAUTION / NOTICE / HINT

Note


  • 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

  • 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

  • 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 at least 60 seconds. Turn the lane departure alert main switch on and then drive the vehicle at a speed of 36 km/h (22 mph) or more for 300 seconds 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

  • If the main body ECU (multiplex network body ECU) is replaced, 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 VEHICLE TYPE


    1. Check vehicle type.

      Result
      Result Proceed to
      for LHD A
      for RHD B

    B

    CHECK FOR SHORT TO GND IN CAN BUS LINE (NO. 1 CAN JUNCTION CONNECTOR) Click here

    A

  2. CHECK FOR SHORT TO GND IN CAN BUS LINE (NO. 1 CAN JUNCTION CONNECTOR)


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

    2. Disconnect the K109 No. 1 CAN junction connector.

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

      B003Y55C80
      *1 DLC3 - -
      *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 Stereo Component Equalizer Assembly

      (w/ ASC System)
      *g to Certification ECU (Smart Key ECU Assembly) *h to Hybrid Vehicle Control ECU Assembly
      *i to Power Steering ECU Assembly - -
      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      K109-1 (CANH) - K9-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher No. 2 CAN junction connector
      K109-11 (CANL) - K9-4 (CG)
      K109-2 (CANH) - K9-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Combination meter assembly
      K109-12 (CANL) - K9-4 (CG)
      K109-4 (CANH) - K9-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Central gateway ECU (network gateway ECU)
      K109-14 (CANL) - K9-4 (CG)
      K109-5 (CANH) - K9-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Air conditioning amplifier assembly
      K109-15 (CANL) - K9-4 (CG)
      K109-6 (CANH) - K9-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Stereo component equalizer assembly*
      K109-16 (CANL) - K9-4 (CG)
      K109-7 (CANH) - K9-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Certification ECU (smart key ECU assembly)
      K109-17 (CANL) - K9-4 (CG)
      K109-8 (CANH) - K9-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Hybrid vehicle control ECU assembly
      K109-18 (CANL) - K9-4 (CG)
      K109-9 (CANH) - K9-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Power steering ECU assembly
      K109-19 (CANL) - K9-4 (CG)

      • *: w/ ASC System

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

    A

    REPLACE NO. 1 CAN JUNCTION CONNECTOR

    C

    GO TO STEP 7 Click here

    D

    CHECK FOR SHORT TO GND IN CAN BUS LINE (CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU)) Click here

    B

  3. CHECK FOR SHORT TO GND IN CAN BUS LINE (NO. 2 CAN JUNCTION CONNECTOR)


    1. Reconnect the K109 No. 1 CAN junction connector.

    2. Disconnect the K110 No. 2 CAN junction connector.

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

      B003Y55C81
      *1 DLC3 - -
      *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 Airbag Sensor Assembly *f to Yaw Rate Sensor
      *g to Steering Sensor *h to Skid Control ECU Assembly
      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      K110-1 (CANH) - K9-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher No. 1 CAN junction connector
      K110-11 (CANL) - K9-4 (CG)
      K110-2 (CANH) - K9-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Main body ECU (multiplex network body ECU)
      K110-12 (CANL) - K9-4 (CG)
      K110-3 (CANH) - K9-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher ECM
      K110-13 (CANL) - K9-4 (CG)
      K110-5 (CANH) - K9-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Airbag sensor assembly
      K110-15 (CANL) - K9-4 (CG)
      K110-6 (CANH) - K9-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Yaw rate sensor
      K110-16 (CANL) - K9-4 (CG)
      K110-9 (CANH) - K9-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Steering sensor
      K110-19 (CANL) - K9-4 (CG)
      K110-10 (CANH) - K9-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Skid control ECU assembly
      K110-20 (CANL) - K9-4 (CG)
      Result
      Result Proceed to
      OK A
      NG (Line to No. 1 CAN junction connector) B
      NG (Line to ECU or sensor) C

    A

    REPLACE NO. 2 CAN JUNCTION CONNECTOR

    B

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

    C

    GO TO STEP 7 Click here

  4. CHECK FOR SHORT TO GND IN CAN BUS LINE (CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))


    1. Disconnect the K146 central gateway ECU (network gateway ECU) connector.

    2. B003YK5C26
      *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
      K146-18 (CA4H) - K146-10 (GND) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      K146-17 (CA4L) - K146-10 (GND)
      Result
      Result
      OK
      NG

    OK

    REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) Click here

    NG

    REPAIR OR REPLACE CAN BRANCH LINE OR CONNECTOR (NO. 1 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))

  5. CHECK FOR SHORT TO GND IN CAN BUS LINE (NO. 1 CAN JUNCTION CONNECTOR)


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

    2. Disconnect the K109 No. 1 CAN junction connector.

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

      B003Y55C84
      *1 DLC3 - -
      *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 Sensor Assembly
      *e to Yaw Rate Sensor *f to Skid Control ECU Assembly
      *g to Steering Sensor - -
      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      K109-1 (CANH) - K9-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher No. 2 CAN junction connector
      K109-11 (CANL) - K9-4 (CG)
      K109-2 (CANH) - K9-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Combination meter assembly
      K109-12 (CANL) - K9-4 (CG)
      K109-4 (CANH) - K9-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Airbag sensor assembly
      K109-14 (CANL) - K9-4 (CG)
      K109-5 (CANH) - K9-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Yaw rate sensor
      K109-15 (CANL) - K9-4 (CG)
      K109-6 (CANH) - K9-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Skid control ECU assembly
      K109-16 (CANL) - K9-4 (CG)
      K109-7 (CANH) - K9-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Steering sensor
      K109-17 (CANL) - K9-4 (CG)
      Result
      Result Proceed to
      OK A
      NG (Line to No. 2 CAN junction connector) B
      NG (Line to ECU or sensor) C

    A

    REPLACE NO. 1 CAN JUNCTION CONNECTOR

    C

    GO TO STEP 7 Click here

    B

  6. CHECK FOR SHORT TO GND IN CAN BUS LINE (NO. 2 CAN JUNCTION CONNECTOR)


    1. Reconnect the K109 No. 1 CAN junction connector.

    2. Disconnect the K110 No. 2 CAN junction connector.

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

      B003Y55C85
      *1 DLC3 - -
      *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 Central Gateway ECU (Network Gateway ECU) *f to Air Conditioning Amplifier Assembly
      *g to Hybrid Vehicle Control ECU Assembly *h to Certification ECU (Smart Key ECU Assembly)
      *i

      to Stereo Component Equalizer Assembly

      (w/ ASC System)

      		 *j to Power Steering ECU Assembly
      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      K110-1 (CANH) - K9-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher No. 1 CAN junction connector
      K110-11 (CANL) - K9-4 (CG)
      K110-2 (CANH) - K9-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Main body ECU (multiplex network body ECU)
      K110-12 (CANL) - K9-4 (CG)
      K110-3 (CANH) - K9-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher ECM
      K110-13 (CANL) - K9-4 (CG)
      K110-5 (CANH) - K9-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Central gateway ECU (network gateway ECU)
      K110-15 (CANL) - K9-4 (CG)
      K110-6 (CANH) - K9-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Air conditioning amplifier assembly
      K110-16 (CANL) - K9-4 (CG)
      K110-7 (CANH) - K9-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Hybrid vehicle control ECU assembly
      K110-17 (CANL) - K9-4 (CG)
      K110-8 (CANH) - K9-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Certification ECU (smart key ECU assembly)
      K110-18 (CANL) - K9-4 (CG)
      K110-9 (CANH) - K9-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Stereo component equalizer assembly*
      K110-19 (CANL) - K9-4 (CG)
      K110-10 (CANH) - K9-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Power steering ECU assembly
      K110-20 (CANL) - K9-4 (CG)

      • *: w/ ASC System

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

    A

    REPLACE NO. 2 CAN JUNCTION CONNECTOR

    B

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

    D

    CHECK FOR SHORT TO GND IN CAN BUS LINE (CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU)) Click here

    C

  7. 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.

      B003Y57C75
      *1 DLC3 - -
      *a

      Component with harness connected

      (Central Gateway ECU (Network Gateway ECU))

      		 - -
      Standard Resistance
      Tester Connection Condition Specified Condition
      K146-18 (CA4H) - K9-4 (CG) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      K146-17 (CA4L) - K9-4 (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 ECU OR SENSOR

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  8. CHECK FOR SHORT TO GND IN CAN BUS LINE (CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))


    1. Disconnect the K146 central gateway ECU (network gateway ECU) connector.

    2. B003YK5C26
      *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
      K146-18 (CA4H) - K146-10 (GND) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher
      K146-17 (CA4L) - K146-10 (GND)
      Result
      Result
      OK
      NG

    OK

    REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) Click here

    NG

    REPAIR OR REPLACE CAN BRANCH LINE OR CONNECTOR (NO. 2 CAN JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))