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Home >> Lexus >> 2007 >> IS 350 >> Repair and Diagnosis >> Restraints >> Air Bag, SRS >> Pre-Collision >> Pre-Collision System >> Diagnosis System

Diagnosis System

  1. CHECK DLC3 
    1. The seat belt control ECU uses CAN and ISO 15765-4 communication protocol. The terminal arrangement of the DLC3 complies with SAE J1962 and matches the ISO 15765-4 format.
      Fig 1: Identifying DLC3 Connector Terminals
      G04996211Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      TERMINALS REFERENCE CHART

      Symbols (Terminals 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 10 to 14 V
      CANH (6) - CANL HIGH - level CAN bus line Engine switch off 54 to 67 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 3 MΩ 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 3 MΩ or higher

      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 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.

      • If the tester is able to communicate when it 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 may be in the tester itself. Consult the tester's instruction manual for information on service or repair of the tester.
  2. FUNCTION OF WARNING INDICATOR AND MESSAGE 
    1. If the pre-collision system is not functioning properly, the driver is warned by the master warning indicator and multi-information display warning message on the combination meter.
      Fig 2: Identifying Warning Indicator And Message
      G05319625Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      WARNING MESSAGE DETAIL

      Master Warning Indicator Warning Message Detail DTC PCS Warning indicator
      ON CHECK PCS SYSTEM This message appears when the seat belt control ECU detects a system malfunction ◦ ON
      Illuminate PCS NOT AVAILABLE NOW This message appears when the seat belt control ECU is in the fail-safe mode (See INITIALIZATION  ) - Blinking
    2. Initial check.
      1. The initial check occurs when the engine switch is off for more than 2 seconds, and then turned on (IG). The initial check consists of a pre-collision system diagnostic check with a duration of approximately 3 seconds.
      2. If a malfunction is detected during the initial check, the multi-information display will output "CHECK PCS SYSTEM" or "PCS NOT AVAILABLE NOW".
        Fig 3: Identifying PCS System
        G05319626Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Constant check.
      1. The seat belt control ECU and distance control ECU constantly monitor the pre-collision system for malfunctions after the initial check approximately 3 seconds after turning the engine switch on (IG).
      2. "CHECK PCS SYSTEM" or "PCS NOT AVAILABLE NOW" is displayed on the multi-information display in the combination meter assembly when the constant check detects malfunctions in the pre-collision system.
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