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Home >> Lexus >> 2007 >> SC 430 >> Repair and Diagnosis >> Restraints >> Restraints Control Systems >> Seat Belt >> SEAT BELT WARNING SYSTEM (w/o Occupant Classification System) >> Diagnosis System

Diagnosis System

  1. DESCRIPTION 
    1. The combination meter controls the functions of the seat belt warning system on the vehicle. Data of the seat belt warning system can be read through 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.
  2. CHECK DLC3 
    1. The ECU uses ISO 15765-4 for communication. The terminal arrangement of the DLC3 complies with SAE J1962 and matches the ISO 15765-4 format.
      Fig 1: Identifying DLC3 Connector Terminals
      G05292402Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      RESISTANCE AND VOLTAGE SPECIFICATION

      Terminal No. (Symbols) Terminal Description Condition Pulse condition
      7 (SIL) - 5 (SG) Bus "+" Line During transmission Pulse generation
      4 (CG) - Body ground Chassis Ground Always Below 1 Ω
      5 (SG) - Body ground Signal ground Always Below 1 Ω
      16 (BAT) - Body ground Battery positive Always 11 to 14 V
      6 (CANH) - 14 (CANL) CAN bus line Ignition switch OFF(1) 54 to 69 Ω
      6 (CANH) - 16 (BAT) HIGH-level CAN bus line Ignition switch OFF(1) 6 kΩ or higher
      6 (CANH) - 4 (CG) HIGH-level CAN bus line Ignition switch OFF(1) 200 Ω or higher
      14 (CANL) - 16 (BAT) LOW-level CAN bus line Ignition switch OFF(1) 6 kΩ or higher
      14 (CANL) - 4 (CG) LOW-level CAN bus line Ignition switch OFF(1) 200 Ω or higher
      NOTE:
      (1) Before measuring the resistance, leave the vehicle as is for at least 1 minute and do not operate the ignition switch, any other switches, or the doors.

      If the result is not as specified, the DLC3 may have a malfunction. Repair or replace the harness and connector.

      HINT:

      Connect the cable of the intelligent tester (with CAN VIM) to the DLC3, turn the ignition switch ON and attempt to use the tester. If the screen displays UNABLE TO CONNECT TO VEHICLE, a problem exists in the vehicle side or the tester side.

      • If communication is normal when the tester is connected to another vehicle, inspect the DLC3 of 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 Intelligent Tester To DLC3
        G05292403Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
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