Diagnosis System

1. The theft warning ECU controls the vehicle's theft deterrent system functions. Theft deterrent system data and the Diagnostic Trouble Codes (DTCs) can be read in the Data Link Connector 3 (DLC3) of the vehicle. When a malfunction occurs in the theft deterrent system, even though the security indicator lamp does not turn on, DTCs can be checked.

   When the system seems to be malfunctioning, use the hand-held tester to check for malfunctions and perform the repairs.

HINT:

The vehicle's ECU uses the ISO 9141-2 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

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 hand-held tester to the DLC3, turn the ignition switch ON and attempt to use the 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 on the original vehicle.
• If communication is still not possible 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 2: Connecting Cable Of Hand-Held Tester To DLC3

  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Standard: 11 to 14 V 

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