Lexus IS250 · Service Manual RESTRAINTS

DIAGNOSIS SYSTEM

Troubleshooting


DESCRIPTION
  1. Data of the system can be read in the Data Link Connector 3 (DLC3) of the vehicle. Therefore, when the system seems to be malfunctioning, use the intelligent tester to check for a malfunction and repair it.


CHECK DLC3
A082779E28
  1. The vehicle's ECM uses ISO 9141-2 communication protocol. The terminal arrangement of the DLC3 complies with SAE J1962 and matches the ISO 9141-2 format.

    Standard:
    Tester Connection
    Condition
    Specified Condition
    7 (Bus + line) - 5 (Signal ground)
    During communication
    Pulse generation
    4 (Chassis ground) - Body ground
    Always
    Below 1 Ω
    5 (Signal ground) - Body ground
    Always
    Below 1 Ω
    16 (B+) - Body ground
    Always
    9 to 14 V

    HINT:
    If the screen displays a communication error message after the cable of the intelligent tester is connected to the DLC3, engine switch on (IG) and used the intelligent tester is used, the problem may be on the vehicle side or tester side.

    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 impossible when the tester is connected to another vehicle, the problem is probably in the tester itself. Consult the Service Department listed in the tester's instruction manual.


INSPECT BATTERY VOLTAGE
  1. Check the battery voltage.

    Standard voltage:
    11 to 14 V

    If the voltage is below 11 V, replace the battery before proceeding.

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