CAN COMMUNICATION SYSTEM Check CAN Bus Line for Short to GND (RHD Models)

DESCRIPTION

There may be a short circuit between the CAN bus main wire and GND when there is no resistance between terminals 6 (CANH) and 4 (CG) or 14 (CANL) and 4 (CG) of the DLC3.

Symptom Trouble Area
No resistance exists between terminals 6 (CANH) and 4 (CG) or 14 (CANL) and 4 (CG) of DLC3.
  • Short to GND in CAN bus main wire

  • Short to GND in CAN bus branch wire

  • Power management control ECU

  • ECM

  • Main body ECU

  • Combination meter

  • Power steering ECU

  • Skid control ECU (Brake booster with master cylinder)

  • Steering angle sensor

  • Yaw rate sensor

  • Center airbag sensor assembly

  • Transmission control ECU

  • Certification ECU

  • Navigation ECU sub-assembly*1

  • Radio and display receiver assembly*2

  • CAN No. 1 junction connector

  • CAN No. 2 junction connector

*1: for Navigation receiver type

*2: for Radio and display type

WIRING DIAGRAM

A01JAT0E02
A01JBKGE06

INSPECTION PROCEDURE

Note


  • Turn the power switch off before measuring the resistances between CAN bus main wires and between CAN bus branch wires.

  • Turn the power switch off before inspecting CAN bus wires for a ground short.

  • After the power switch is turned off, check that the key reminder warning system and light reminder warning system are not operating.

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

Tech Tips


  • Operating the power 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 TO GND IN CAN BUS WIRE (CAN NO. 1 J/C)


    1. Turn the power switch off.

    2. A01JAQEE52
      Text in Illustration
      *1

      Front view of wire harness connector

      (to CAN No. 1 Junction Connector)

      *2 to CAN No. 2 Junction Connector

      Disconnect the CAN No. 1 junction connector.

    3. A01JBRRE05
      Text in Illustration
      *3 DLC3

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      L61-6 (CANH) - L61-4 (CG) Power switch off 200 Ω or higher
      L61-14 (CANL) - L61-4 (CG) Power switch off 200 Ω or higher

    NG
    OK
  2. CHECK FOR SHORT TO GND IN CAN BUS WIRE (CAN NO. 1 J/C)

    A01JDACE18

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      L94-1 (CANH) - L61-4 (CG) Power switch off 200 Ω or higher Combination meter
      L94-12 (CANL) - L61-4 (CG) Power switch off 200 Ω or higher
      L94-2 (CANH) - L61-4 (CG) Power switch off 200 Ω or higher Main body ECU
      L94-13 (CANL) - L61-4 (CG) Power switch off 200 Ω or higher
      L94-4 (CANH) - L61-4 (CG) Power switch off 200 Ω or higher Yaw rate sensor
      L94-15 (CANL) - L61-4 (CG) Power switch off 200 Ω or higher
      L94-5 (CANH) - L61-4 (CG) Power switch off 200 Ω or higher Center airbag sensor assembly
      L94-16 (CANL) - L61-4 (CG) Power switch off 200 Ω or higher
      L94-6 (CANH) - L61-4 (CG) Power switch off 200 Ω or higher Power management control ECU
      L94-17 (CANL) - L61-4 (CG) Power switch off 200 Ω or higher
      L94-7 (CANH) - L61-4 (CG) Power switch off 200 Ω or higher Transmission control ECU
      L94-18 (CANL) - L61-4 (CG) Power switch off 200 Ω or higher
      Text in Illustration
      *1

      Front view of wire harness connector

      (to CAN No. 1 Junction Connector)

      *2 DLC3
      *3 to Combination Meter *4 to Main Body ECU
      *5 to Yaw Rate sensor *6 to Center Airbag Sensor Assembly
      *7 to Power Management Control ECU *8 to Transmission Control ECU
      Result
      Result Proceed to
      OK A
      NG (to ECU or sensor wire) B

    B
    A
  3. CHECK FOR SHORT TO GND IN CAN BUS WIRE (CAN NO. 2 J/C)


    1. Disconnect the CAN No. 2 junction connector.

      A01JDACE19
      Text in Illustration
      *1

      Front view of wire harness connector

      (to CAN No. 2 Junction Connector)

      *2 DLC3
      *3 to Steering Angle Sensor *4 to Power Steering ECU
      *5 to Skid Control ECU *6 to DLC3
      *7
      • to Navigation ECU Sub-assembly*1

      • to Radio and Display Receiver Assembly*2

      *8 to CAN No. 1 Junction Connector
      *9 to Certification ECU *10 to ECM
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      L95-1 (CANH) - L61-4 (CG) Power switch off 200 Ω or higher Steering angle sensor
      L95-12 (CANL) - L61-4 (CG) Power switch off 200 Ω or higher
      L95-2 (CANH) - L61-4 (CG) Power switch off 200 Ω or higher Power steering ECU
      L95-13 (CANL) - L61-4 (CG) Power switch off 200 Ω or higher
      L95-3 (CANH) - L61-4 (CG) Power switch off 200 Ω or higher Skid control ECU
      L95-14 (CANL) - L61-4 (CG) Power switch off 200 Ω or higher
      L95-4 (CANH) - L61-4 (CG) Power switch off 200 Ω or higher DLC3
      L95-15 (CANL) - L61-4 (CG) Power switch off 200 Ω or higher
      L95-5 (CANH) - L61-4 (CG) Power switch off 200 Ω or higher
      • Navigation ECU sub-assembly*1

      • Radio and display receiver assembly*2

      L95-16 (CANL) - L61-4 (CG) Power switch off 200 Ω or higher
      L95-6 (CANH) - L61-4 (CG) Power switch off 200 Ω or higher CAN No. 1 junction connector
      L95-17 (CANL) - L61-4 (CG) Power switch off 200 Ω or higher
      L95-7 (CANH) - L61-4 (CG) Power switch off 200 Ω or higher Certification ECU
      L95-18 (CANL) - L61-4 (CG) Power switch off 200 Ω or higher
      L95-9 (CANH) - L61-4 (CG) Power switch off 200 Ω or higher ECM
      L95-20 (CANL) - L61-4 (CG) Power switch off 200 Ω or higher

      *1: for Navigation receiver type

      *2: for Radio and display type

      Result
      Result Proceed to
      OK A
      NG (to DLC3 branch wire) B
      NG (to CAN No. 1 J/C main wire) C
      NG (to ECU or sensor wire) D

    B
    C
    D
    A
  4. CHECK FOR SHORT TO GND IN CAN BUS WIRE (ECU, SENSOR)


    1. Reconnect the CAN No. 1 junction connector and CAN No. 2 junction connector wire harness connector.

    2. Disconnect the ECU or sensor connected to the CAN bus wire that is shorted to ground.

      Tech Tips

      If the ECU or sensor has multiple connectors, disconnect the connector that includes the CAN bus wires. To determine the ECU or sensor that is connected to the shorted bus wire, refer to the terminals of ECU tables Click here.

    3. A01JBRRE02
      Text in Illustration
      *1 DLC3

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      L61-6 (CANH) - L61-4 (CG) Power switch off 200 Ω or higher
      L61-14 (CANL) - L61-4 (CG) Power switch off 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).


    NG
    OK