CAN COMMUNICATION SYSTEM(w/ Central Gateway ECU) Open in Bus 2 Main Bus Line (LHD Models)

DESCRIPTION

There may be an open circuit in one of the CAN main bus lines 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 the central gateway ECU (network gateway ECU) is 70 Ω or higher.

  • CAN main bus lines or connector

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

  • ECM

  • Combination meter sub-assembly

  • No. 1 CAN junction connector

  • No. 2 CAN junction connector

  • No. 3 CAN junction connector

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

WIRING DIAGRAM

B005YX3E04

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), turn the cruise control system on using the cruise control switch (ON/OFF switch), wait at least 60 seconds, and then drive the vehicle at a speed of 50 km/h (31 mph) or more for at least 1.72 seconds.

  • 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.

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 OPEN IN CAN BUS LINES (CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))


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

    2. Disconnect the L192 central gateway ECU (network gateway ECU) connector.

    3. B005XRNE02
      Text in Illustration
      *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
      L192-18 (CA4H) - L192-17 (CA4L) Cable disconnected from negative (-) auxiliary 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 (ECM)


    1. B005YVYE01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to ECM)

      Disconnect the A57 ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A57-13 (CANH) - A57-5 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω

    OK

    REPLACE ECM Click here

    NG

  3. CHECK FOR OPEN IN CAN BUS LINES (COMBINATION METER SUB-ASSEMBLY)


    1. Reconnect the A57 ECM connector.

    2. B005Z3QE02
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Combination Meter Sub-assembly)

      Disconnect the L27 combination meter sub-assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      L27-19 (CANH) - L27-20 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω

    OK

    REPLACE COMBINATION METER SUB-ASSEMBLY Click here

    NG

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


    1. Reconnect the L27 combination meter sub-assembly connector.

    2. B005YLNE03
      Text in Illustration
      *a

      Front view of wire harness connector

      (to No. 2 CAN Junction Connector)
      *b to No. 3 CAN Junction Connector
      *c to No. 1 CAN Junction Connector

      Disconnect the L94 wire harness connector from the No. 2 CAN junction connector (instrument panel connector holder left side).

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      L94-2 (CANH) -L94-1 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω No. 3 CAN junction connector
      L94-5 (CANH) - L94-4 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω No. 1 CAN junction connector
      Result
      Result Proceed to
      OK A
      NG (Line to No. 1 CAN junction connector) B
      NG (Line to No. 3 CAN junction connector) C

    A

    REPLACE NO. 2 CAN JUNCTION CONNECTOR

    C

    CHECK FOR OPEN IN CAN BUS LINES (NO. 3 CAN JUNCTION CONNECTOR) Click here

    B

  5. CHECK FOR OPEN IN CAN BUS LINES (NO. 2 CAN JUNCTION CONNECTOR - NO. 1 CAN JUNCTION CONNECTOR)


    1. Reconnect the L94 wire harness connector to the No. 2 CAN junction connector (instrument panel connector holder left side).

    2. B005XQYE02
      Text in Illustration
      *a

      Front view of wire harness connector

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

      Disconnect the L132 wire harness connector from the No. 1 CAN junction connector (instrument panel wire side).

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      L132-6 (CANH) - L132-12 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω

    NG

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

    OK

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


    1. B005YAAE03
      Text in Illustration
      *a

      Front view of wire harness connector

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

      Disconnect the A67 wire harness connector from the No. 1 CAN junction connector (engine room main wire side).

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A67-1 (CANH) - A67-7 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω

    OK

    REPLACE NO. 1 CAN JUNCTION CONNECTOR

    NG

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

  7. CHECK FOR OPEN IN CAN BUS LINES (NO. 3 CAN JUNCTION CONNECTOR)


    1. Reconnect the L94 wire harness connector to the No. 2 CAN junction connector (instrument panel connector holder left side).

    2. B005Y7CE02
      Text in Illustration
      *a

      Front view of wire harness connector

      (to No. 3 CAN Junction Connector)
      *b to No. 2 CAN Junction Connector
      *c to Combination Meter Sub-assembly

      Disconnect the L133 wire harness connector from the No. 3 CAN junction connector (instrument panel wire side).

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      L133-5 (CANH) -L133-11 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω No. 2 CAN junction connector
      L133-6 (CANH) - L133-12 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 108 to 132 Ω Combination meter sub-assembly
      Result
      Result Proceed to
      OK A
      NG (Line to No. 2 CAN junction connector) B
      NG (Line to Combination meter sub-assembly) C

    A

    REPLACE NO. 3 CAN JUNCTION CONNECTOR

    B

    REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 2 CAN JUNCTION CONNECTOR - NO. 3 CAN JUNCTION CONNECTOR)

    C

    REPAIR OR REPLACE CAN MAIN BUS LINES OR CONNECTOR (NO. 3 CAN JUNCTION CONNECTOR - COMBINATION METER SUB-ASSEMBLY))