Lexus IS250 · Service Manual BODY ELECTRICAL

DIAGNOSIS SYSTEM

Troubleshooting


DESCRIPTION
  1. Smart access system with push-button start data and the Diagnostic Trouble Codes (DTCs) can be read in the Data Link Connector 3 (DLC3) of the vehicle. When the system seems to be malfunctioning, use the intelligent tester to check for malfunctions and perform repairs.


CHECK DLC3
A082779E48
  1. The vehicle uses ISO 15765-4 for communication protocol. The terminal arrangement of the DLC3 complies with ISO 15031-03 and matches the ISO 15765-4 format.

    Symbols (Terminal No.)
    Terminal Description
    Condition
    Specified Condition
    SIL (7) - SG (5)
    Bus "+" line
    During transmission
    Pulse generation
    CG (4) - Body ground
    Chassis ground
    Always
    Below 1 Ω
    SG (5) - Body ground
    Signal ground
    Always
    Below 1 Ω
    BAT (16) - Body ground
    Battery positive
    Always
    11 to 14 V
    CANH (6) - CANL (14)
    HIGH-level CAN bus line
    Engine switch OFF
    54 to 69 Ω
    CANH (6) - Battery positive (+)
    HIGH-level CAN bus line
    Engine switch OFF
    1 MΩ or higher
    CANH (6) - CG (4)
    HIGH-level CAN bus line
    Engine switch OFF
    1 kΩ or higher
    CANL (14) - Battery positive (+)
    LOW-level CAN bus line
    Engine switch OFF
    1 MΩ or higher
    CANL (14) - CG (4)
    LOW-level CAN bus line
    Engine switch OFF
    1 kΩ or higher
    1. If the result is not as specified, the DLC3 may have a malfunction. Repair or replace the harness and connector.

  2. C123647E01
    Intelligent Tester

    HINT:
    Connect the cable of the intelligent tester to the DLC3, turn the engine switch on (IG) and attempt to use the tester. If the display indicates that a communication error has occurred, there is a problem either with the vehicle or with the tester.
    1. If communication is normal when the tester is connected to another vehicle, inspect the DLC3 of the original vehicle.
    2. If communication is still not possible when the tester is connected to another vehicle, the problem may be in the tester itself. Consult the Service Department listed in the tester's instruction manual.

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