CAN COMMUNICATION SYSTEM Check Bus 4 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 22 (CA2H) and 7 (CA2L) of the central gateway ECU (network gateway ECU) is below 54 Ω.

Symptom Trouble Area
Resistance between terminals 22 (CA2H) and 7 (CA2L) of the central gateway ECU (network gateway ECU) is below 54 Ω.

  • Short in CAN main bus wire

  • Short in CAN branch wire

  • Central gateway ECU (network gateway ECU)

  • Steering sensor

  • Rack and pinion power steering gear assembly

  • Airbag ECU assembly

  • ECM

  • Yaw rate sensor

  • Skid control ECU assembly

  • Hybrid vehicle control ECU assembly

  • Pedestrian detection ECU assembly

  • Rear steering control ECU*1

  • Parking brake ECU assembly

  • Absorber control ECU

  • Suspension control ECU*2

  • Tire pressure warning ECU and receiver

  • Front steering control ECU*3

  • Occupant detection ECU*4

  • No. 1 CAN junction terminal

  • No. 2 CAN junction terminal

  • No. 4 CAN junction connector

  • No. 12 CAN junction connector

  • No. 14 CAN junction connector
*1: w/ Dynamic Rear Steering System
*2: w/ Air Suspension System
*3: w/ Variable Gear Ratio Steering System
*4: w/ Occupant Classification System

WIRING DIAGRAM

B004X48E05
B004TJGE05

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 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

  • Some parts must be initialized and set when replacing or removing and installing parts.

    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 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

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 WIRES (NO. 4 CAN JUNCTION CONNECTOR)


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

    2. Disconnect the G122 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 Connected to
      G122-12 (CANH) - G122-1 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω No. 12 CAN junction connector
      G122-13 (CANH) - G122-2 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Central gateway ECU (network gateway ECU)
      G122-14 (CANH) - G122-3 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Steering sensor
      G122-15 (CANH) - G122-4 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω No. 14 CAN junction connector
      G122-16 (CANH) - G122-5 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Airbag ECU assembly
      G122-17 (CANH) - G122-6 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Yaw rate sensor
      G122-18 (CANH) - G122-7 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Pedestrian detection ECU assembly
      G122-19 (CANH) - G122-8 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Front steering control ECU*
      G122-21 (CANH) - G122-10 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Hybrid vehicle control ECU assembly
      *: w/ Variable Gear Ratio Steering System
      Result
      Result Proceed to
      OK A
      NG (Central gateway ECU [network gateway ECU] CAN branch wire) B
      NG (No. 12 CAN junction connector CAN main wire) C
      NG (No. 14 CAN junction connector CAN main wire) D
      NG (Wire to ECU or sensor) E

    A

    REPLACE NO. 4 CAN JUNCTION CONNECTOR

    C

    CHECK FOR SHORT IN CAN BUS WIRES (NO. 12 CAN JUNCTION CONNECTOR) Click here

    D

    CHECK FOR SHORT IN CAN BUS WIRES (NO. 14 CAN JUNCTION CONNECTOR) Click here

    E

    CHECK FOR SHORT IN CAN BUS WIRES (ECU, SENSOR) Click here

    B

  2. CHECK FOR SHORT IN CAN BUS WIRES (CENTRAL GATEWAY ECU [NETWORK GATEWAY ECU] - NO. 4 CAN JUNCTION CONNECTOR)


    1. Reconnect the G122 No. 4 CAN junction connector.

    2. Disconnect the G66 central gateway ECU (network gateway ECU) connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G66-22 (CA2H) - G66-7 (CA2L) Cable disconnected from negative (-) auxiliary battery terminal 54 to 69 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) Click here

    NG

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

  3. CHECK FOR SHORT IN CAN BUS WIRES (NO. 12 CAN JUNCTION CONNECTOR)


    1. Reconnect the G122 No. 4 CAN junction connector.

    2. Disconnect the L117 No. 12 CAN junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      L117-1 (CANH) - L117-7 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Skid control ECU assembly
      L117-2 (CANH) - L117-8 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω No. 4 CAN junction connector
      L117-3 (CANH) - L117-9 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω No. 2 CAN junction terminal
      L117-5 (CANH) - L117-11 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Rack and pinion power steering gear assembly
      L117-6 (CANH) - L117-12 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher ECM
      Result
      Result Proceed to
      OK A
      NG (No. 2 CAN junction terminal CAN main wire) B
      NG (No. 4 CAN junction terminal CAN main wire) C
      NG (Wire to ECU or sensor) D

    A

    REPLACE NO. 12 CAN JUNCTION CONNECTOR

    C

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 12 CAN JUNCTION CONNECTOR - NO. 4 CAN JUNCTION CONNECTOR)

    D

    GO TO STEP 7 Click here

    B

  4. CHECK FOR SHORT IN CAN BUS WIRES (NO. 2 CAN JUNCTION TERMINAL - NO. 12 CAN JUNCTION CONNECTOR)


    1. Reconnect the L117 No. 12 CAN junction connector.

    2. Disconnect the L122 No. 2 CAN junction terminal connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      L122-3 (CANH) - L122-2 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE NO. 2 CAN JUNCTION TERMINAL

    NG

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 2 CAN JUNCTION TERMINAL - NO. 12 CAN JUNCTION CONNECTOR)

  5. CHECK FOR SHORT IN CAN BUS WIRES (NO. 14 CAN JUNCTION CONNECTOR)


    1. Reconnect the G122 No. 4 CAN junction connector.

    2. Disconnect the L119 No. 14 CAN junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      L119-1 (CANH) - L119-11 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω No. 1 CAN junction terminal
      L119-2 (CANH) - L119-12 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω No. 4 CAN junction connector
      L119-3 (CANH) - L119-13 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Parking brake ECU assembly
      L119-4 (CANH) - L119-14 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Absorber control ECU
      L119-5 (CANH) - L119-15 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Tire pressure warning ECU and receiver
      L119-7 (CANH) - L119-17 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Suspension control ECU*1
      L119-8 (CANH) - L119-18 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Rear steering control ECU*2
      L119-9 (CANH) - L119-19 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 200 Ω or higher Occupant detection ECU*3
      *1: w/ Air Suspension System
      *2: w/ Dynamic Rear Steering System
      *3: w/ Occupant Classification System
      Result
      Result Proceed to
      OK A
      NG (No. 1 CAN junction terminal CAN main wire) B
      NG (No. 4 CAN junction connector CAN main wire) C
      NG (Wire to ECU or sensor) D

    A

    REPLACE NO. 14 CAN JUNCTION CONNECTOR

    C

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 14 CAN JUNCTION CONNECTOR - NO. 4 CAN JUNCTION CONNECTOR)

    D

    GO TO STEP 7 Click here

    B

  6. CHECK FOR SHORT IN CAN BUS WIRES (NO. 1 CAN JUNCTION TERMINAL - NO. 14 CAN JUNCTION CONNECTOR)


    1. Reconnect the L119 No. 14 CAN junction connector.

    2. Disconnect the L121 No. 1 CAN junction terminal connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      L121-3 (CANH) - L121-2 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE NO. 1 CAN JUNCTION TERMINAL

    NG

    REPAIR OR REPLACE CAN MAIN WIRE OR CONNECTOR (NO. 1 CAN JUNCTION TERMINAL - NO. 14 CAN JUNCTION CONNECTOR)

  7. CHECK FOR SHORT IN CAN BUS WIRES (ECU, SENSOR)


    1. B004S4IC51
      *a

      Component with harness connected

      (Central Gateway ECU [Network Gateway ECU])

      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 wire is connected.

      Click here

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      G66-22 (CA2H) - G66-7 (CA2L) Cable disconnected from negative (-) auxiliary 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.

      Result
      Proceed to
      OK
      NG

    OK

    REPLACE ECU OR SENSOR

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR