CAN COMMUNICATION SYSTEM Short to B+ in CAN Bus Line

DESCRIPTION

A short to B+ is suspected in the CAN bus line when there is continuity between terminals 16 (BAT) and 6 (CANH) or terminals 16 (BAT) and 14 (CANL) of the DLC3.

Symptom Trouble Area
There is continuity between terminals 16 (BAT) and 6 (CANH) or 16 (BAT) and 14 (CANL) of the DLC3.

  • Short to B+ in CAN bus line

  • ECM

  • Air conditioning complifier

WIRING DIAGRAM

A01BBJEE02

INSPECTION PROCEDURE

PROCEDURE


  1. CHECK CAN BUS LINE FOR SHORT TO B+ (DLC3 SUB BUS LINE)


    1. A01BFF5E05

      Disconnect the DLC3 sub bus line connector (H5) from the CAN J/C.

      Note


      • Before disconnecting the connector, make a note of where it is connected.

      • Reconnect the connector to its original position.

    2. A01BI1KE22

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

      Standard resistance
      Tester connection Condition Specified value
      H23-16 (BAT) - H23-6 (CANH) IG switch OFF 1 MΩ or higher

      H23-16 (BAT) -

      H23-14 (CANL)

      		 IG switch OFF 1 MΩ or higher

      Tech Tips


      • NG-A: Resistance between terminals BAT and CANH is less than 1 MΩ.

      • NG-B: Resistance between terminals BAT and CANL is less than 1 MΩ.


    NG-A

    REPAIR OR REPLACE DLC3 SUB BUS LINE OR CONNECTOR (CAN-H)

    NG-B

    REPAIR OR REPLACE DLC3 SUB BUS LINE OR CONNECTOR (CAN-L)

    OK

  2. CONNECT CONNECTOR


    1. Reconnect the DLC3 sub bus line connector (H5) to the CAN J/C.


    NEXT

  3. CHECK CAN BUS LINE FOR SHORT TO B+ (AIR CONDITIONING AMPLIFIER SUB BUS LINE)


    1. A01BFF5E07

      Disconnect the air conditioning amplifier sub bus line connector (H3) from the CAN J/C.

      Note


      • Before disconnecting the connector, make a note of where it is connected.

      • Reconnect the connector to its original position.

    2. A01BI1KE22

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

      Standard resistance
      Tester connection Condition Specified value
      H23-16 (BAT) - H23-6 (CANH) IG switch OFF 1 MΩ or higher

      H23-16 (BAT) -

      H23-14 (CANL)

      		 IG switch OFF 1 MΩ or higher

    OK

    CHECK CAN BUS LINE FOR SHORT TO B+ (AIR CONDITIONING AMPLIFIER SUB BUS LINE) Click here

    NG

  4. CONNECT CONNECTOR


    1. Reconnect the air conditioning amplifier sub bus line connector (H3) to the CAN J/C.


    NEXT

  5. CHECK CAN BUS LINE FOR SHORT TO B+ (ECM MAIN BUS LINE)


    1. A01BFF5E08

      Disconnect the ECM main bus line connector (H4) from the CAN J/C.

      Note


      • Before disconnecting the connector, make a note of where it is connected.

      • Reconnect the connector to its original position.

    2. A01BAYNE03

      Disconnect the ECM connectors (B7) and (B9). (2TR-FE)

    3. Disconnect the ECM connector (B7). (2KD-FTV)

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

      Standard resistance
      2TR-FE
      Tester connection Condition Specified value
      B7-33 (CANH) - B9-3 (BATT) IG switch OFF 1 MΩ or higher
      B7-34 (CANL) - B9-3 (BATT) IG switch OFF 1 MΩ or higher
      1KD-FTV, 2KD-FTV
      Tester connection Condition Specified value
      B7-24 (CANH) - B7-2 (BATT) IG switch OFF 1 MΩ or higher
      B7-23 (CANL) - B7-2 (BATT) IG switch OFF 1 MΩ or higher

      Tech Tips


      • NG-A: Resistance between terminals BATT and CANH is less than 1 MΩ.

      • NG-B: Resistance between terminals BATT and CANL is less than 1 MΩ.


    NG-A

    REPAIR OR REPLACE ECM MAIN BUS LINE OR CONNECTOR (CAN-H)

    NG-B

    REPAIR OR REPLACE ECM MAIN BUS LINE OR CONNECTOR (CAN-L)

    OK

    REPLACE ECM

  6. CHECK CAN BUS LINE FOR SHORT TO B+ (AIR CONDITIONING AMPLIFIER SUB BUS LINE)


    1. A01BHX5E07

      Disconnect the air conditioning amplifier (H18).

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

      Standard resistance
      Tester connection Condition Specified value
      H18-10 (CANH) - H18-40 (B) IG switch OFF 1 MΩ or higher
      H18-11 (CANL) - H18-40 (B) IG switch OFF 1 MΩ or higher

      Tech Tips


      • Check the air conditioning amplifier sub bus line line connector (H3) while disconnected from the CAN J/C.

      • NG-A: Resistance between terminals B and CANH is less than 1 MΩ.

      • NG-B: Resistance between terminals B and CANL is less than 1 MΩ.


    NG-A

    REPAIR OR REPLACE AIR CONDITIONING AMPLIFIER SUB BUS LINE OR CONNECTOR (CAN-H)

    NG-B

    REPAIR OR REPLACE AIR CONDITIONING AMPLIFIER SUB BUS LINE OR CONNECTOR (CAN-L)

    OK

    REPLACE AIR CONDITIONING AMPLIFIER