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.

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.

   HINT:

   Connect the cable of the intelligent tester (with CAN VIM) to the DLC3, turn the ignition switch on (IG) and attempt to use the intelligent tester. If the screen displays a communication error message, a problem exists on the vehicle side or the tester side. If the communication is normal when the tester is connected to another vehicle, inspect the DLC3 on the original vehicle.

   If the communication is still impossible 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 1: Identifying DLC3 Connectors

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   DLC3 CONNECTOR TERMINALS VOLTAGE AND RESISTANCE SPECIFICATION
   
   

   Symbol (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 1 Ω
   BAT (16) - Body ground	Battery positive	Always	11 to 14 V

Standard: 

11 to 14 V 

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