CAN COMMUNICATION SYSTEM(w/ Toyota Safety Sense) Open in Bus 2 Main Bus Line

DESCRIPTION

There may be an open circuit in one of the bus 2 main lines and/or a central gateway ECU (network gateway ECU) branch line when the resistance between terminals 18 (CA4H) and 17 (CA4L) of the central gateway ECU (network gateway ECU) is 70 Ω or higher.

Symptom Trouble Area
Resistance between terminals 18 (CA4H) and 17 (CA4L) of central gateway ECU (network gateway ECU) is 70 Ω or higher.

  • Central gateway ECU (network gateway ECU) branch line or connector

  • CAN main bus line or connector

  • ECM

  • Combination meter assembly

  • No. 1 junction connector

  • No. 2 junction connector

This malfunction is not related to the lines of a bus 2 main bus branch or to ECUs or sensors connected a bus 2 main bus branch.

WIRING DIAGRAM

A004AA2E03

CAUTION / NOTICE / HINT

Note


  • Turn the ignition switch off before measuring the resistances of the CAN main wire and the CAN branch wire.

  • After the ignition switch is turned off, check that the key reminder warning system and light reminder warning system are not in operation.

  • Before measuring the resistance, leave the vehicle as is for at least 1 minute and do not operate the ignition switch, any other switches or the doors. If doors need to be opened in order to check connectors, open the doors and leave them open.

Tech Tips

Operating the ignition switch, any switches or any doors triggers related ECU and sensor communication with the CAN, which causes resistance variation.

PROCEDURE


  1. CHECK FOR OPEN IN CAN BUS LINES (CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))


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

    2. A0048HWE02
      Text in Illustration
      *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
      F135-18 (CA4H) - F135-17 (CA4L) Cable disconnected from negative (-) battery terminal 108 to 132 Ω

      Note

      When the measured value is 133 Ω or higher and a CAN communication system DTC is output, there may be a fault besides disconnection of the central gateway ECU (network gateway ECU) branch line. For that reason, troubleshooting should be performed again from How to Proceed with Troubleshooting after repairing the trouble area Click here.


    NG

    REPAIR OR REPLACE CAN BRANCH LINE CONNECTED TO CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU)

    OK

  2. CHECK FOR OPEN IN CAN BUS LINES (COMBINATION METER ASSEMBLY - NO. 2 JUNCTION CONNECTOR)


    1. A0046YYE02
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Combination Meter Assembly)

      Disconnect the combination meter assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      F1-32 (CANH) - F1-31 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω

    OK

    REPLACE COMBINATION METER ASSEMBLY Click here

    NG

  3. CHECK FOR OPEN IN CAN BUS LINES (ECM - NO. 1 JUNCTION CONNECTOR)


    1. Reconnect the F1 combination meter assembly connector.

    2. A0048XKE02
      Text in Illustration
      *A for 2NR-FKE
      *B for 1KR-FE
      *C for 1ND-TV without DPF
      *D for 1ND-TV with DPF
      *a

      Front view of wire harness connector

      (to ECM)

      Disconnect the ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition

      A58-13 (CANH) - A58-26 (CANL)*1

      A93-26 (CANH) - A93-25 (CANL)*2

      A59-3 (CANH) - A59-4 (CANL)*3

      A108-26 (CANH) - A108-25 (CANL)*4

      		 Cable disconnected from negative (-) battery terminal 108 to 132 Ω

      *1: for 2NR-FKE

      *2: for 1KR-FE

      *3: for 1ND-TV without DPF

      *4: for 1ND-TV with DPF

      Result
      Result Proceed to
      NG A
      OK (for 2NR-FKE) B
      OK (for 1KR-FE) C
      OK (for 1ND-TV with DPF) D
      OK (for 1ND-TV without DPF) E

    B

    REPLACE ECM Click here

    C

    REPLACE ECM Click here

    D

    REPLACE ECM Click here

    E

    REPLACE ECM Click here

    A

  4. CHECK FOR OPEN IN CAN BUS LINES (NO. 2 JUNCTION CONNECTOR)


    1. Reconnect the A58*1, A93*2, A59*3 or A108*4 ECM connector.

      *1: for 2NR-FKE

      *2: for 1KR-FE

      *3: for 1ND-TV without DPF

      *4: for 1ND-TV with DPF

    2. A0047V1E02
      Text in Illustration
      *a

      Front view of wire harness connector

      (to No. 2 Junction Connector)
      *b to Combination Meter Assembly
      *c to No. 1 Junction Connector

      Disconnect the No. 2 junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      F83-7 (CANH) - F83-18 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Combination meter assembly
      F83-10 (CANH) - F83-21 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω No. 1 junction connector
      Result
      Result Proceed to
      OK A
      NG (Combination meter assembly main line) B
      NG (No. 1 junction connector main line) C

    A

    REPLACE NO. 2 JUNCTION CONNECTOR

    B

    REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (NO. 2 JUNCTION CONNECTOR - COMBINATION METER ASSEMBLY)

    C

  5. CHECK FOR OPEN IN CAN BUS LINES (NO. 1 JUNCTION CONNECTOR)


    1. Reconnect the F83 No. 2 junction connector.

    2. A0049YAE02
      Text in Illustration
      *a

      Front view of wire harness connector

      (to No. 1 Junction Connector)
      *b to No. 2 Junction Connector

      Disconnect the No. 1 junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      F136-4 (CANH) - F136-15 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω No. 2 junction connector

    NG

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

    OK

  6. CHECK FOR OPEN IN CAN BUS LINES (NO. 1 JUNCTION CONNECTOR)


    1. Reconnect the F136 No. 1 junction connector.

    2. A0047SNE02
      Text in Illustration
      *a

      Front view of wire harness connector

      (to No. 1 Junction Connector)
      *b to ECM

      Disconnect the No. 1 junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      A110-9 (CANH) - A110-20 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω ECM

    OK

    REPLACE NO. 1 JUNCTION CONNECTOR

    NG

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