Diagnosis System

DESCRIPTION
1. The active control engine mount ECU controls the functions of the CAN communication system on the vehicle. Data of the CAN communication system and the Diagnostic Trouble Codes (DTCs) can be read through the Data Link Connector 3 (DLC3) of the vehicle.

CHECK DLC3

The vehicle's ECU uses ISO 15765-4 for communication protocol. The terminal arrangement of the DLC3 complies with SAE J1962 and matches the ISO 15765-4 format.

Fig 1: Identifying Terminals Of DLC3 Connector

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

DLC3 CONNECTOR - TERMINALS REFERENCE CHART

Symbols	Terminal No.	Names	Reference terminal	Results	Condition
SIL	7	Bus "+" line	5 - Signal ground	Pulse generation	During transmission
CG	4	Chassis ground	Body ground	1 Ω or less	Always
SG	5	Signal ground	Body ground	1 Ω or less	Always
BAT	16	Battery ground	Body ground	9 to 14 V	Always
CANH	6	CAN "High" line	CANL	54 to 69 Ω	Engine switch off
CANH	6	CAN "High" line	Battery positive	6 kΩ or higher	Engine switch off
CANH	6	CAN "High" line	CG	200 Ω or higher	Engine switch off
CANL	14	CAN "Low" line	Battery positive	6 kΩ or higher	Engine switch off
CANL	14	CAN "Low" line	CG	200 Ω or higher	Engine switch off

HINT:

The DLC3 is the interface prepared for reading various data from the vehicle's ECU. After connecting the cable of Techstream, turn the engine switch on (IG) and turn the tester on. If a communication failure message is displayed on the tester screen, a problem exists in either the vehicle or tester. In order to identify the location of the problem, connect the tester to another vehicle. If communication is normal: Inspect the DLC3 on the original vehicle.

If communication is still not possible: The problem is probably in the tester itself. Consult the Service Department listed in the instruction manual.

Techstream
HINT:

Connect the cable of Techstream 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 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 may be in the tester itself. Consult the Service Department listed in the tester's instruction manual.

INSPECT BATTERY VOLTAGE
Standard Voltage:

11 to 14 V

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