CAN COMMUNICATION SYSTEM Check CAN Bus Lines for Short Circuit

DTC Code DTC Name
Check CAN Bus Lines for Short Circuit

DESCRIPTION

There may be a short circuit between the V bus main lines and/or CAN branch lines when the resistance between terminals 6 (CANH) and 14 (CANL) of the DLC3 is below 54 Ω.

Symptom

Trouble Area

Resistance between terminals 6 (CANH) and 14 (CANL) of DLC3 is below 54 Ω.

  • Short in CAN main bus lines

  • Short in CAN branch lines

  • Combination meter assembly

  • Power steering ECU assembly

  • Steering sensor (spiral cable sub-assembly)*1

  • Airbag sensor assembly

  • ECM

  • Skid control ECU (brake actuator assembly)

  • Certification ECU (smart key ECU assembly)*2

  • Engine stop and start ECU*3

  • Radio and display receiver assembly*4

  • Air conditioning control assembly*5

  • Pre-crash safety city sensor*6

  • No. 1 CAN junction connector

  • *1: w/ VSC

  • *2: w/ Entry and Start System

  • *3: w/ Stop and Start System

  • *4: for Radio and Display Type

  • *5: for Automatic Air Conditioning System

  • *6: w/ Toyota Safety Sense

WIRING DIAGRAM

C301058E01
C328535E01

CAUTION / NOTICE / HINT

Note:

  • Before measuring the resistance of the CAN bus, turn the ignition switch off and leave the vehicle for 1 minute or more without operating the key or 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 ignition 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.

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  • 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.

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  • After performing repairs, perform the DTC check procedure and confirm that the DTCs are not output again.

  • DTC check procedure: Turn the ignition switch to ON and wait at least 83 seconds, and then drive the vehicle at a speed of 20 km/h (12 mph) or more for 8.42 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.

    Click here

Tip:

  • Operating the ignition switch, any other switches or a door triggers related ECU and sensor communication on the CAN. This communication will cause the resistance value to change.

  • 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 IN CAN BUS LINES (COMBINATION METER ASSEMBLY - NO. 1 CAN JUNCTION CONNECTOR)

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

    2. C304159C04

      *a

      Front view of wire harness connector

      (to Combination Meter Assembly)

      Disconnect the E12 combination meter assembly connector.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      E12-37 (CANH) - E12-36 (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 - NO. 1 CAN JUNCTION CONNECTOR)

    1. Reconnect the E12 combination meter assembly connector.

    2. C301206C01

      *A

      for 1KR-FE

      *B

      for 1PP

      *a

      Front view of wire harness connector

      (to ECM)

      Disconnect the A34 or A35 ECM connector.

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

      Standard Resistance

      Table 1. for 1KR-FE

      Tester Connection

      Condition

      Specified Condition

      A34-26 (CANH) - A34-25 (CANL)

      Cable disconnected from negative (-) battery terminal

      108 to 132 Ω
      Table 2. for 1PP

      Tester Connection

      Condition

      Specified Condition

      A35-40 (CANH) - A35-52 (CANL)

      Cable disconnected from negative (-) battery terminal

      108 to 132 Ω

    Result

    Result

    Proceed to

    OK (for 1KR-FE)

    A

    OK (for 1PP)

    B

    NG

    C
    A

    REPLACE ECM

    Click here

    B

    REPLACE ECM

    Click here

    C

  3. CHECK FOR SHORT IN CAN BUS LINES (NO. 1 CAN JUNCTION CONNECTOR (ENGINE ROOM MAIN WIRE))

    1. Reconnect the A34 or A35 ECM connector.

    2. C289288C21

      *a

      Front view of wire harness connector

      (to No. 1 CAN Junction Connector)

      *b

      to ECM

      *c

      to Skid Control ECU (Brake Actuator Assembly)

      *d

      to Engine Stop and Start ECU

      (w/ Stop and Start System)

      Disconnect the A59 No. 1 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

      A59-1 (CANH) - A59-12 (CANL)

      Cable disconnected from negative (-) battery terminal

      108 to 132 Ω

      ECM

      A59-2 (CANH) - A59-13 (CANL)

      Cable disconnected from negative (-) battery terminal

      200 Ω or higher

      Skid control ECU (brake actuator assembly)

      A59-3 (CANH) - A59-14 (CANL)

      Cable disconnected from negative (-) battery terminal

      200 Ω or higher

      Engine stop and start ECU*

    *: w/ Stop and Start System

    Result

    Result

    Proceed to

    OK

    A

    NG (ECU or sensor branch line)

    B

    NG (ECM main line)

    C
    B

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

    C

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

    A

  4. CHECK FOR SHORT IN CAN BUS LINES (NO. 1 CAN JUNCTION CONNECTOR (INSTRUMENT PANEL WIRE))

    1. Reconnect the A59 No. 1 CAN junction connector.

    2. Disconnect the E2 No. 1 CAN junction connector.

      C281852C85

      *a

      Front view of wire harness connector

      (to No. 1 CAN Junction Connector)

      *b

      to Airbag Sensor Assembly

      *c

      to Radio and Display Receiver Assembly

      (for Radio and Display Type)

      *d

      to Combination Meter Assembly

      *e

      to Air Conditioning Control Assembly

      (for Automatic Air Conditioning System)

      *f

      to Power Steering ECU Assembly

      *g

      to Steering Sensor (Spiral Cable Sub-assembly)

      (w/ VSC)

      *h

      to DLC3

      *i

      to Certification ECU (Smart Key ECU Assembly)

      (w/ Entry and Start System)

      *j

      to Pre-crash Safety City Sensor

      (w/ Toyota Safety Sense)

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      Connected to

      E2-1 (CANH) - E2-12 (CANL)

      Cable disconnected from negative (-) battery terminal

      200 Ω or higher

      Airbag sensor assembly

      E2-2 (CANH) - E2-13 (CANL)

      Cable disconnected from negative (-) battery terminal

      200 Ω or higher

      Radio and display receiver assembly*1

      E2-4 (CANH) - E2-15 (CANL)

      Cable disconnected from negative (-) battery terminal

      108 to 132 Ω

      Combination meter assembly

      E2-5 (CANH) - E2-16 (CANL)

      Cable disconnected from negative (-) battery terminal

      200 Ω or higher

      Air conditioning control assembly*2

      E2-6 (CANH) - E2-17 (CANL)

      Cable disconnected from negative (-) battery terminal

      200 Ω or higher

      Power steering ECU assembly

      E2-7 (CANH) - E2-18 (CANL)

      Cable disconnected from negative (-) battery terminal

      200 Ω or higher

      Steering sensor (spiral cable sub-assembly)*3

      E2-8 (CANH) - E2-19 (CANL)

      Cable disconnected from negative (-) battery terminal

      1 MΩ or higher

      DLC3

      E2-9 (CANH) - E2-20 (CANL)

      Cable disconnected from negative (-) battery terminal

      200 Ω or higher

      Certification ECU (smart key ECU assembly)*4

      E2-10 (CANH) - E2-21 (CANL)

      Cable disconnected from negative (-) battery terminal

      200 Ω or higher

      Pre-crash safety city sensor*5

      • *1: for Radio and Display Type

      • *2: for Automatic Air Conditioning System

      • *3: w/ VSC

      • *4: w/ Entry and Start System

      • *5: w/ Toyota Safety Sense

    Result

    Result

    Proceed to

    OK

    A

    NG (ECU or sensor branch line)

    B

    NG (DLC3 branch line)

    C

    NG (Combination meter assembly main line)

    D
    A

    REPLACE NO. 1 CAN JUNCTION CONNECTOR

    C

    REPAIR OR REPLACE CAN BRANCH LINE CONNECTED TO DLC3

    D

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

    B

  5. CHECK FOR SHORT IN CAN BUS LINES (ECU, 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. C151827C65

      *1

      DLC3

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      E8-6 (CANH) - E8-14 (CANL)

      Cable disconnected from negative (-) battery terminal

      54 to 69 Ω
      Tip:

      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

    Result

    OK

    NG
    OK

    REPLACE CORRESPONDING ECU OR SENSOR

    NG

    REPAIR OR REPLACE CORRESPONDING ECU OR SENSOR BRANCH LINES OR CONNECTOR