CAN COMMUNICATION SYSTEM Check CAN Bus Lines for Short Circuit

DESCRIPTION

There may a short circuit in the CAN main wire and/or CAN branch wire when the resistance between terminals 10 (CANH) and 9 (CANL) of the yaw rate sensor connector is below 54 Ω.

Symptom Trouble Area
Resistance between terminals 10 (CANH) and 9 (CANL) of yaw rate sensor connector below 54 Ω

  • Short between CAN bus lines

  • ABS and traction actuator (skid control ECU)

  • Steering sensor

  • Yaw rate sensor

  • ECM

  • Transmission Control ECU*1

  • CAN junction connector

*1: w/ Multi-mode manual transaxle system

WIRING DIAGRAM

A013855E01

INSPECTION PROCEDURE

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 light reminder warning system is 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 CAN BUS LINES FOR SHORT CIRCUIT (CAN JUNCTION CONNECTOR - ECM)


    1. Turn the ignition switch off.

    2. A0137N2E03
      Text in Illustration
      *a

      Front view of wire harness connector

      (to CAN Junction Connector)

      Disconnect the CAN junction connector.

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      A38-8 (CAN+) - A38-2 (CAN-) Ignition switch off 108 to 132 Ω

    NG

    CHECK CAN BUS LINES FOR SHORT CIRCUIT (ECM MAIN WIRE) Click here

    OK

  2. CHECK CAN BUS LINES FOR SHORT CIRCUIT (CAN JUNCTION CONNECTOR - YAW RATE SENSOR)


    1. A0137N2E05
      Text in Illustration
      *a

      Front view of wire harness connector

      (to CAN Junction Connector)

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

      Tech Tips

      The resistance must be measured after the A38 CAN junction connector is disconnected.

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      A38-7 (CANH) - A38-1 (CANL) Ignition switch off 1 MΩ or higher

    NG

    CHECK CAN BUS LINES FOR SHORT CIRCUIT (YAW RATE SENSOR BRANCH WIRE) Click here

    OK

  3. CHECK CAN BUS LINES FOR SHORT CIRCUIT (CAN JUNCTION CONNECTOR - TRANSMISSION CONTROL ECU)

    Tech Tips

    For vehicle without multi-mode manual transaxle system, go to step 4.


    1. A0137N2E06
      Text in Illustration
      *a

      Front view of wire harness connector

      (to CAN Junction Connector)

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

      Tech Tips

      The resistance must be measured after the A38 CAN junction connector is disconnected.

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      A38-10 (CAN+) - A38-4 (CAN-) Ignition switch off 1 MΩ or higher

    NG

    CHECK CAN BUS LINES FOR SHORT CIRCUIT (TRANSMISSION CONTROL ECU BRANCH WIRE) Click here

    OK

  4. CHECK CAN BUS LINES FOR SHORT CIRCUIT (CAN JUNCTION CONNECTOR - ABS AND TRACTION ACTUATOR (SKID CONTROL ECU))


    1. A0137N2E07
      Text in Illustration
      *a

      Front view of wire harness connector

      (to CAN Junction Connector)

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

      Tech Tips

      The resistance must be measured after the A38 CAN junction connector is disconnected.

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      A38-9 (CANH) - A38-3 (CANL) Ignition switch off 1 MΩ or higher

    NG

    CHECK CAN BUS LINES FOR SHORT CIRCUIT (ABS AND TRACTION ACTUATOR (SKID CONTROL ECU) BRANCH WIRE) Click here

    OK

  5. CONNECT CONNECTOR


    1. Reconnect the A38 CAN junction connector.


    NEXT

  6. CHECK CAN BUS LINES FOR SHORT CIRCUIT (CAN JUNCTION CONNECTOR - STEERING SENSOR)


    1. A0137N2E04
      Text in Illustration
      *a

      Front view of wire harness connector

      (to CAN Junction Connector)

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

      Tech Tips

      The resistance must be measured after the C42 CAN junction connector is disconnected.

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      C42-10 (CANH) - C42-4 (CANL) Ignition switch off 108 to 132 Ω

    NG

    CHECK CAN BUS LINES FOR SHORT CIRCUIT (STEERING SENSOR MAIN WIRE) Click here

    OK

    REPLACE CAN JUNCTION CONNECTOR

  7. CHECK CAN BUS LINES FOR SHORT CIRCUIT (ECM MAIN WIRE)


    1. A0136ABE05
      Text in Illustration
      *a

      Front view of wire harness connector

      (to ECM)

      Disconnect the ECM connector.

    2. A0137N2E04
      Text in Illustration
      *a

      Front view of wire harness connector

      (to CAN Junction Connector)

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

      Tech Tips

      The resistance must be measured after the A38 CAN junction connector is disconnected.

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      A38-8 (CAN+) - A38-2 (CAN-) Ignition switch off 1 MΩ or higher
      Result
      Result Proceed to
      NG A
      OK B

    B

    REPLACE ECM Click here

    A

    REPAIR OR REPLACE CAN MAIN WIRE CONNECTED TO ECM (CAN-H, CAN-L)

  8. CHECK CAN BUS LINES FOR SHORT CIRCUIT (YAW RATE SENSOR BRANCH WIRE)


    1. A0136DHE02
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Yaw Rate Sensor)

      Disconnect the yaw rate sensor connector.

    2. A0137N2E05
      Text in Illustration
      *a

      Front view of wire harness connector

      (to CAN Junction Connector)

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

      Tech Tips

      The resistance must be measured after the A38 CAN junction connector is disconnected.

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      A38-7 (CANH) - A38-1 (CANL) Ignition switch off 1 MΩ or higher

    NG

    REPAIR OR REPLACE CAN BRANCH WIRE CONNECTED TO YAW RATE SENSOR (CAN-H, CAN-L)

    OK

    REPLACE YAW RATE SENSOR Click here

  9. CHECK CAN BUS LINES FOR SHORT CIRCUIT (TRANSMISSION CONTROL ECU BRANCH WIRE)


    1. A0137RXE06
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Transmission Control ECU)

      Disconnect the transmission control ECU connector.

    2. A0137N2E06
      Text in Illustration
      *a

      Front view of wire harness connector

      (to CAN Junction Connector)

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

      Tech Tips

      The resistance must be measured after the A38 CAN junction connector is disconnected.

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      A38-10 (CAN+) - A38-4 (CAN-) Ignition switch off 1 MΩ or higher

    NG

    REPAIR OR REPLACE CAN BRANCH WIRE CONNECTED TO TRANSMISSION CONTROL ECU (CAN-H, CAN-L)

    OK

    REPLACE TRANSMISSION CONTROL ECU Click here

  10. CHECK CAN BUS LINES FOR SHORT CIRCUIT (ABS AND TRACTION ACTUATOR (SKID CONTROL ECU) BRANCH WIRE)


    1. Disconnect the ABS and traction actuator (skid control ECU) connector.

      A01364GE07
      Text in Illustration
      *a

      Front view of wire harness connector

      (to ABS and Traction Actuator (Skid Control ECU))

      		 - -
    2. A0137N2E07
      Text in Illustration
      *a

      Front view of wire harness connector

      (to CAN Junction Connector)

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

      Tech Tips

      The resistance must be measured after the A38 CAN junction connector is disconnected.

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      A38-9 (CANH) - A38-3 (CANL) Ignition switch off 1 MΩ or higher

    NG

    REPAIR OR REPLACE CAN BRANCH WIRE CONNECTED TO ABS AND TRACTION ACTUATOR (SKID CONTROL ECU) (CAN-H, CAN-L)

    OK

    REPLACE ABS AND TRACTION ACTUATOR (SKID CONTROL ECU) Click here

  11. CHECK CAN BUS LINES FOR SHORT CIRCUIT (STEERING SENSOR MAIN WIRE)


    1. A0138ZPE03
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Steering Sensor)

      Disconnect the steering sensor connector.

    2. A0137N2E04
      Text in Illustration
      *a

      Front view of wire harness connector

      (to CAN Junction Connector)

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

      Tech Tips

      The resistance must be measured after the C42 CAN junction connector is disconnected.

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      C42-10 (CANH) - C42-4 (CANL) Ignition switch off 1 MΩ or higher

    NG

    REPAIR OR REPLACE CAN MAIN WIRE CONNECTED TO STEERING SENSOR (CAN-H, CAN-L)

    OK

    REPLACE STEERING SENSOR Click here