CAN COMMUNICATION SYSTEM > Check CAN Bus Line (LHD Models)

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DESCRIPTION

When any DTC for the CAN communication system is output, first measure the resistance between the terminals of the DLC3 to specify the trouble area, and check that there is no short in the CAN main bus line, between the CAN bus lines, to +B, or to GND.

WIRING DIAGRAM


C112570E02


C112571E01


C112572E01


INSPECTION PROCEDURE

1.CHECK CAN BUS MAIN LINE (MAIN BUS LINE FOR DISCONNECTION, BUS LINES FOR SHORT CIRCUIT)

  1. Turn the engine switch off.



    G026206E28

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

    Standard resistance:
    Tester Connection
    		Condition
    		Specified Value
    		Result
    L16-6 (CANH) - L16-14 (CANL)
    		Engine switch off
    		54 to 69 Ω
    		OK
    L16-6 (CANH) - L16-14 (CANL)
    		Engine switch off
    		69 Ω or more
    		NG-A
    L16-6 (CANH) - L16-14 (CANL)
    		Engine switch off
    		54 Ω or less
    		NG-B



NG-A
CHECK CAN MAIN BUS LINE FOR DISCONNECTION

NG-B
CHECK CAN BUS LINES FOR SHORT CIRCUIT
OK


2.CHECK CAN BUS LINE FOR SHORT TO +B


    G026206E29

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

    Standard resistance:
    Tester Connection
    		Condition
    		Specified Value
    L16-6 (CANH) - L16-16 (BAT)
    		Engine switch off
    		1 MΩ or more
    L16-14 (CANL) - L16-16 (BAT)
    		Engine switch off
    		1 MΩ or more



NG
CHECK CAN BUS LINE FOR SHORT TO +B
OK


3.CHECK CAN BUS LINE FOR SHORT TO GND


    G026206E30

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

    Standard resistance:
    Tester Connection
    		Condition
    		Specified Value
    L16-6 (CANH) - L16-16 (BAT)
    		Engine switch off
    		1 MΩ or more
    L16-14 (CANL) - L16-16 (BAT)
    		Engine switch off
    		1 MΩ or more



NG
CHECK CAN BUS LINE FOR SHORT TO GND
OK

HOW TO PROCEED WITH TROUBLESHOOTING