Diagnosis System

The certification ECU controls the function of the smart key system on the vehicle. Data of the smart key system and the Diagnostic Trouble Code (DTC) can be read in the Data Link Connector 3 (DLC3) of the vehicle. When a malfunction occurs in the smart key system, even though the smart key system warning light does not turn on, DTCs can be checked.

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

HINT:

The vehicle uses the 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 DLC3 Terminals

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 engine switch on (IG) and attempt to use the hand-held tester. If the screen displays a communication error message, a problem may be on the vehicle side or tester side.

• When troubleshooting the smart key system using the hand-held tester with the engine switch off, connect the hand-held tester to the vehicle and repeat turning any of the courtesy light switches on and off until communication between the tester and the vehicle begins (the interval between ON and OFF should be less than 1.5 sec).
• If communication is normal when the tester is connected to another vehicle, inspect the DLC3 of the original vehicle.
• If communication is still impossible 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.
  Fig 2: Connecting Hand Held Tester To DLC3

  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Standard: 11 to 14 V 

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