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Home >> Lexus >> 2005 >> SC 430 >> Repair and Diagnosis >> Electrical >> Gauges >> Combination Meter - Diagnostics >> Diagnosis System

Diagnosis System

  1. CHECK DLC3 

    The vehicle's ECM uses ISO 9141-2 for communicating. The terminal arrangement of the DLC3 complies with SAE J1962 and matches the ISO 9141-2 format.

    Fig 1: Checking DLC3
    G02956767Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    DLC3

    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 ohms
    SG (5) - Body ground Signal ground Always Below 1 ohms
    BAT (16) - Body ground Battery positive Always 11 to 14 V

    HINT:

    Connect the cable of the hand-held tester to the DLC3, turn the ignition switch ON 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.

    • If communication is normal when the hand-held tester is connected to another vehicle, inspect the DLC3 on the original vehicle.
    • If communication is still not possible 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.
      Fig 2: Connecting Cable Of Hand-Held Tester To DLC3
      G02956768Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  2. INSPECT BATTERY VOLTAGE 

    Standard: 11 to 14 V 

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