Diagnosis System

1. DESCRIPTION 
   1. When troubleshooting a vehicle with the diagnosis system, the only difference from the usual troubleshooting procedure is connecting the Techstream to the vehicle and reading various data output from the vehicle's clearance warning ECU. The clearance warning ECU records DTCs when the ECU detects a malfunction in the ECU itself or in its circuits.

      To check the DTCs, connect the Techstream to the DLC3 on the vehicle. The Techstream enables you to erase the DTCs, activate the various actuators, and check the freeze frame data and Data List.

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

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      DLC3 TERMINAL REFERENCE
      
      

      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	11 to 14 V
      CANH (6) - CANL (14)	CAN bus line	Power switch OFF(1)	54 to 69 Ω
      CANH (6) - CG (4)	HIGH-level CAN bus line	Power switch OFF(1)	200 Ω or more
      CANL (14) - CG (4)	LOW-level CAN bus line	Power switch OFF(1)	200 Ω or more
      CANH (6) - BAT (16)	HIGH-level CAN bus line	Power switch OFF(1)	6 kΩ or more
      CANL (14) - BAT (16)	LOW-level CAN bus line	Power switch OFF(1)	6 kΩ or more
      (1) Before measuring the resistance, leave the vehicle as is for at least 1 minute and do not operate the power 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 Techstream to the DLC3, turn the power switch on (IG) and attempt to use the Techstream. If the display indicates that a communication error has occurred, there is a problem either with the vehicle or with the Techstream.

• If communication is normal when the Techstream is connected to another vehicle, inspect the DLC3 of the original vehicle.
• If communication is still not possible when the Techstream is connected to another vehicle, the problem may be in the Techstream itself. Consult the Service Department listed in the Techstream's instruction manual.