CAN COMMUNICATION SYSTEM Short to GND in CAN Bus Line

DESCRIPTION

A short to GND is suspected in the CAN bus line when there is continuity between terminals 4 (CG) and 6 (CANH) or terminals 4 (CG) and 14 (CANL) of the DLC3.

Symptom Trouble Area
There is continuity between terminals 4 (CG) and 6 (CANH) or terminals 4 (CG) and 14 (CANL) of the DLC3.

  • Short to GND in CAN bus line

  • ECM

  • Air conditioning amplifier

  • CAN J/C

WIRING DIAGRAM

A01BH4QE02

INSPECTION PROCEDURE

PROCEDURE


  1. CHECK CAN BUS LINE SHORT TO GND (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. A01BI1KE23

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

      Tech Tips


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

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

      Standard resistance
      Tester connection Condition Specified value
      H23-4 (CG) - H23-6 (CANH) IG switch OFF 1 MΩ or higher
      H23-4 (CG) - H23-14 (CANL) IG switch OFF 1 MΩ or higher

    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 SHORT TO GND (AIR CONDITIONING AMPLIFIER SUB BUS LINE)


    1. A01BFF5E06

      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. A01BI1KE23

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

      Standard resistance
      Tester connection Condition Specified value
      H23-4 (CG) - H23-6 (CANH) IG switch OFF 3 kΩ or higher
      H23-4 (CG) - H23-14 (CANL) IG switch OFF 3 kΩ or higher

    OK

    CHECK CAN BUS LINE SHORT TO GND (AIR CONDITIONING AMPLIFIER SUB BUS LINE) Click here

    NG

  4. CONNECTOR CONNECT


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


    NEXT

  5. CHECK CAN BUS LINE SHORT TO GND (ECM MAIN BUS LINE)


    1. A01BFF5E04

      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. A01BI1KE23

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

      Standard resistance
      Tester connection Condition Specified value
      H23-4 (CG) - H23-6 (CANH) IG switch OFF 3 kΩ or higher
      H23-4 (CG) - H23-14 (CANL) IG switch OFF 3 kΩ or higher

    OK

    CHECK CAN BUS LINE SHORT TO GND (ECM MAIN BUS LINE) Click here

    NG

    REPLACE CAN J/C

  6. CHECK CAN BUS LINE SHORT TO GND (AIR CONDITIONING AMPLIFIER SUB BUS LINE)


    1. Disconnect the air conditioning amplifier connector (H18).

    2. A01BHX5E06

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

      Standard resistance
      Tester connection Condition Specified value

      H18-10 (CANH) -

      H18-29 (GND)

      		 IG switch OFF 1 MΩ or higher

      H18-11 (CANL) -

      H18-29 (GND)

      		 IG switch OFF 1 MΩ or higher

      Tech Tips


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

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

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


    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

  7. CHECK CAN BUS LINE SHORT TO GND (ECM MAIN BUS LINE)


    1. A01BF48E02

      Disconnect the ECM connectors (B7) and (D1). (2TR-FE)

    2. Disconnect the ECM connector (B7) and (D3). (1KD-FTV, 2KD-FTV)

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

      Standard resistance
      2TR-FE
      Tester Connection Condition Specified value

      B7-33 (CANH) -

      D1-3 (E1)

      		 IG switch OFF 1 MΩ or higher

      B7-34 (CANL) -

      D1-3 (E1)

      		 IG switch OFF 1 MΩ or higher
      1KD-FTV, 2KD-FTV
      Tester Connection Condition Specified value

      B7-24 (CANH) -

      D3-7 (E1)

      		 IG switch OFF 1 MΩ or higher

      B7-23 (CANL) -

      D3-7 (E1)

      		 IG switch OFF 1 MΩ or higher

      Tech Tips


      • NG-A: Resistance between terminals E1 and CANH is less than 1 MΩ.

      • NG-B: Resistance between terminals E1 and CANL is less than 1 MΩ.

      • Check the ECM main bus line connector (H4) while disconnected from the CAN J/C.


    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