Diagnosis System

WARNING: This page is about a different car, the 2004 Lexus LS 430. However, it is still accessible from the selected car via links, so may be relevant.

CHECK DLC3
1. The vehicle's combination meter (ECU) uses CAN and the 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 Terminals
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 2: DLC3 Terminals Reference Chart
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
HINT:

If the display shows UNABLE TO CONNECT TO VEHICLE when you have connected the cable of the hand-held tester to the DLC3, turned the ignition switch ON and operated the tester, there is a problem on the vehicle side or tool side.
- If the communication is normal when the tool is connected to another vehicle, inspect the DLC3 on the original vehicle.
- If the communication is still impossible when the tool is connected to another vehicle, the problem is probably in the tool itself, so consult the Service Department listed in the tool's instruction manual.
DIAGNOSIS CHECK (MULTI-INFORMATION DISPLAY)
1. Switch to diagnosis mode
  1. Connect terminal 13 (TC) and 4 (CG) of the DLCS using SST.
    
    Fig 3: Identifying DLC3 Terminals (TC And CG)
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  2. The display in the warning area shows "DIAG" when the ignition switch is turned to the ON position.
  3. Each system can be switched by pushing the "DISP1" switch on the steering pad switch.
  HINT:
  
  Diagnosis checks for the EFI, VSC and CRUISE systems can be done by using the displayed items in the warning area.
  - SFI (EFI) system (see HOW TO PROCEED WITH TROUBLESHOOTING )
  - VSC system (see HOW TO PROCEED WITH TROUBLESHOOTING )
  - CRUISE system (see HOW TO PROCEED WITH TROUBLESHOOTING )
    
    Fig 4: Diagnosis System Check - Multi-Information Display (1 Of 3)
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Read DTCs
  1. "OK" is displayed if the system is normal while "NG" is displayed if it is malfunctioning.
  HINT:
  
  When the ignition switch is turned to any position but ON during diagnosis mode, the mode is canceled.
  
  Fig 5: Diagnosis System Check - Multi-Information Display (2 Of 3)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. "- -" is displayed if there is an open or short circuit in communication lines between the meter and each ECU being checked. "E" is displayed if there is a problem with diagnosis communication signal data.
  
  Fig 6: Diagnosis System Check - Multi-Information Display (3 Of 3)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002