Diagnosis System

DESCRIPTION
1. Engine immobilizer system data and Diagnostic Trouble Codes (DTCs) can be read through the vehicle's Data Link Connector 3 (DLC3). In some cases, a malfunction may occur in the immobilizer system even though the security indicator is not illuminated. When the system seems to be malfunctioning, use the hand-held tester to check for malfunctions and perform repairs.

CHECK DLC3

HINT:

The vehicle uses ISO 9141-2 for communication protocol. The terminal arrangement of the DLC3 complies with SAE J1962 and matches the ISO 9141-2 format.

Fig 1: Identifying DLC3 Connector Terminal

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

TERMINAL DESCRIPTION

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 ohms
SG (5) - Body ground	Signal ground	Always	Below 1 ohms
BAT (16) - Body ground	Battery positive	Always	11 to 14 V

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

Fig 2: Connecting Cable Of Hand-Held Tester To DLC3

HINT:

Connect the cable of the hand-held tester to the DLC3, turn the ignition switch ON and attempt to use tester. If the screen displays the message UNABLE TO CONNECT TO VEHICLE, 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 is probably in the tester. Consult the Service Department listed in the tester's instruction manual.

INSPECT BATTERY VOLTAGE
Standard: 11 to 14 V

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