CAN COMMUNICATION SYSTEM Check Bus 5 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 15 (CA5H) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3, or terminal 16 (CA5L) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3.

Symptom Trouble Area
No resistance exists between terminal 15 (CA5H) of the central gateway ECU (network gateway ECU) and terminal 4 (CG) of the DLC3, or terminal 16 (CA5L) 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)

  • Driving support ECU assembly

    (w/ Toyota Safety Sense)

  • Millimeter wave radar sensor assembly

    (w/ Toyota Safety Sense)

  • Forward recognition camera

    (w/ Toyota Safety Sense)

  • Parking assist ECU

    (w/ Panoramic View Monitor System)

  • Television camera assembly

    (w/ Parking Assist Monitor System)

  • Blind spot monitor sensor LH

    (w/ Blind Spot Monitor System)

  • No. 1 CAN junction connector

  • No. 2 CAN junction connector

  • CAN junction terminal

WIRING DIAGRAM

A002BYOE02
A002BKUE02

CAUTION / NOTICE / HINT

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 ignition 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 (-) 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.

    Click here

  • 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 20 seconds. Turn the cruise control main switch on and then drive the vehicle at a speed of 36 km/h (22 mph) or more for 9 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

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 TO GND IN CAN BUS LINE (NO. 2 CAN JUNCTION CONNECTOR - CAN JUNCTION TERMINAL)


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

    2. A0028S7C02
      *1 DLC3
      *a

      Rear view of wire harness connector

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

      Disconnect the M41 wire harness connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      M41-1 (CANH) - F25-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      M41-2 (CANL) - F25-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher

      Note


      • Before disconnecting the connectors, make a note of where they are connected.

      • Reconnect each connector to its original position.

      Result
      Result
      OK
      NG

    NG

    CHECK FOR SHORT TO GND IN CAN BUS LINE (CAN JUNCTION TERMINAL) Click here

    OK

  2. CHECK FOR SHORT TO GND IN CAN BUS LINE


    1. Reconnect the M41 wire harness connector.

    2. A002B37C14
      *1 DLC3
      *a

      Component with harness connected

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

      Connect the probes of an electrical tester to terminals 1 (CANH) and 2 (CANL) of the M41 wire harness connector and CG of the DLC3.

    3. While observing the resistance value shown on the electrical tester, disconnect the F105, F108, F110, F132, F133, M39 and M40 connectors from the No. 1 CAN junction connector and No. 2 CAN junction connector until the resistance becomes normal (200 Ω or higher (for ground short)).

      A0029MTC01
      *A w/ Toyota Safety Sense *B w/ Panoramic View Monitor System
      *C w/ Blind Spot Monitor System *D w/ Parking Assist Monitor System
      *1 Central Gateway ECU (Network Gateway ECU) *2 Forward Recognition Camera
      *3 Driving Support ECU Assembly *4 Millimeter Wave Radar Sensor Assembly
      *5 Parking Assist ECU *6 CAN Junction Terminal
      *7 Blind Spot Monitor Sensor LH *8 Television Camera Assembly
      *9 No. 1 CAN Junction Connector *10 No. 2 CAN Junction Connector
      A002922C01
      *a

      Component without harness connected

      (No. 1 CAN Junction Connector)

      		 - -
      Wiring Color
      No. 1 CAN Junction Connector Side Code Color (CANH Side) Color (CANL Side)
      No. 2 CAN junction connector F104 BR W
      Central gateway ECU (network gateway ECU) F105 L W
      Forward recognition camera*1 F108 R W
      Driving support ECU assembly*1 F110 G W
      Millimeter wave radar sensor assembly*1 F133 P W
      Parking assist ECU*2 F134 LG W

      • *1: w/ Toyota Safety Sense

      • *2: w/ Panoramic View Monitor System

      A002CC1C04
      *a

      Component without harness connected

      (No. 2 CAN Junction Connector)

      		 - -
      Wiring Color
      No. 2 CAN Junction Connector Side Code Color (CANH Side) Color (CANL Side)
      No. 1 CAN junction connector M38 BR W
      Television camera assembly*1 M39 B W
      Blind spot monitor sensor LH*2 M40 GR W
      CAN junction terminal M41 B W

      • *1: w/ Parking Assist Monitor System

      • *2: w/ Blind Spot Monitor System

      Result
      Result Proceed to

      The resistance between terminals CANH and GND, or the resistance between terminals CANL and GND is still below 200 Ω when all the specified connectors are disconnected from the CAN junction connector.

      (There is a short to GND in the CAN main bus lines between the No. 1 CAN junction connector and No. 2 CAN junction connector.)

      		 A

      The resistance between terminals CANH and GND, or the resistance between terminals CANL and GND becomes normal (200 Ω or higher) when a connector is disconnected from the CAN junction connector.

      (There is a short to GND in one of the areas that relate to the disconnected bus lines.)

      		 B

    B

    CHECK FOR SHORT TO GND IN CAN BUS LINE (ECU OR SENSOR) Click here

    A

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


    1. Reconnect all wire harness connectors.

    2. Disconnect the M38 wire harness connector.

    3. A0029VTC05
      *1 DLC3
      *a

      Component with harness connected

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

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      M41-1 (CANH) - F25-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      M41-2 (CANL) - F25-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher

      Note


      • Before disconnecting the connectors, make a note of where they are connected.

      • Reconnect each connector to its original position.

      Result
      Result
      OK
      NG

    NG

    REPLACE NO. 2 CAN JUNCTION CONNECTOR

    OK

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


    1. Reconnect the M38 wire harness connector.

    2. Disconnect the F104 wire harness connector.

    3. A002B37C15
      *1 DLC3
      *a

      Component with harness connected

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

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      M41-1 (CANH) - F25-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      M41-2 (CANL) - F25-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher

      Note


      • Before disconnecting the connectors, make a note of where they are connected.

      • Reconnect each connector to its original position.

      Result
      Result
      OK
      NG

    OK

    REPLACE NO. 1 CAN JUNCTION CONNECTOR

    NG

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

  5. 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. A002B37C16
      *1 DLC3
      *a

      Component with harness connected

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

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      M41-1 (CANH) - F25-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      M41-2 (CANL) - F25-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher

      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 CORRESPONDING ECU OR SENSOR

    NG

    REPAIR OR REPLACE CORRESPONDING ECU OR SENSOR BRANCH LINE OR CONNECTOR

  6. CHECK FOR SHORT TO GND IN CAN BUS LINE (CAN JUNCTION TERMINAL)


    1. Reconnect the M41 wire harness connector.

    2. Disconnect the M42 CAN junction terminal connector.

    3. A002AG2C43
      *1 DLC3
      *a

      Front view of wire harness connector

      (to CAN Junction Terminal)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      M42-3 (CANH) - F25-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      M42-2 (CANL) - F25-4 (CG) Cable disconnected from negative (-) battery terminal 200 Ω or higher
      Result
      Result
      OK
      NG

    OK

    REPLACE CAN JUNCTION TERMINAL

    NG

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