Diagnosis System

1. Multiplex communication system data can be read in 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 make necessary repairs.

Standard: 

11 to 14 V 

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

1. The vehicle's ECU uses the 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

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   TERMINALS REFERENCE
   
   

   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 Ω
   SG (5) - Body ground	Signal ground	Always	Below Ω
   BAT (16) - Body ground	Battery positive	Always	11 to 14 V
   CANH (6) - CANL (14)	CAN bus line	Ignition switch off(1)	54 to 69 Ω
   CANH (6) - CG (4)	HIGH-level CAN bus line	Ignition switch off(1)	200 Ω or higher
   CANL (14) - CG (4)	LOW-level CAN bus line	Ignition switch off(1)	200 Ω or higher
   CANH (6) - BAT (16)	HIGH-level CAN bus line	Ignition switch off(1)	6 kΩ or higher
   CANL (14) - BAT (16)	LOW-level CAN bus line	Ignition switch off(1)	6 kΩ or higher
   NOTE: (1) Before measuring the resistance, leave the vehicle as it is for at least 1 minute and do not operate the ignition switch, or any other switches or the doors.

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

   HINT:

   • If communication is normal when the tester is connected to another vehicle, inspect 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 instruction manual.