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*

  • CAN junction connector

*: w/ Multi-mode manual transaxle system

WIRING DIAGRAM

A0138M2E02

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 J/C - ECM)


    1. Turn the ignition switch off.

    2. A01373EE01

      Disconnect the A38 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 J/C - YAW RATE SENSOR)


    1. A01373EE02

      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 J/C - TRANSMISSION CONTROL ECU)

    Tech Tips

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


    1. A01373EE03

      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 J/C - ABS AND TRACTION ACTUATOR (SKID CONTROL ECU))


    1. A01373EE04

      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 J/C - DLC3)

    Tech Tips

    For 1KR-FE, go to step 7.


    1. Turn the ignition switch off.

    2. A01373EE05

      Disconnect the C42 CAN junction connector.

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

      Standard Resistance
      Tester Connection Switch Condition Specified Condition
      C42-7 (CANH) - C42-1 (CANL) Ignition switch off 1 MΩ or higher

    NG

    REPAIR OR REPLACE CAN BRANCH WIRE CONNECTED TO DLC3 (CAN-H, CAN-L)

    OK

  7. CHECK CAN BUS LINES FOR SHORT CIRCUIT (CAN J/C - STEERING SENSOR)


    1. A01373EE06

      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

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


    1. A0138J1E02

      Disconnect the B26, A35 or A36 ECM connector.

    2. A01373EE01

      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 (for 1KR-FE) B
      OK (for 2WZ-TV) C

    B

    REPLACE ECM Click here

    C

    REPLACE ECM Click here

    A

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

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


    1. A0137APE03

      Disconnect the H25 yaw rate sensor connector.

    2. A01373EE02

      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

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


    1. A0137SWE03

      Disconnect the A28 transmission control ECU connector.

    2. A01373EE03

      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

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


    1. Disconnect the A41 ABS and traction actuator (skid control ECU) connector.

      A01364GE04
    2. A01373EE04

      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

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


    1. A0136YUE05

      Disconnect the C43 steering sensor connector.

    2. A01373EE06

      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