Description of On-Board Diagnostics

DESCRIPTION




a. DIAGNOSIS SYSTEM
When troubleshooting Multiplex OBD (M-OBD) vehicles, the only difference from the usual troubleshooting procedure is that you connect the LEXUS hand-held tester to vehicle, and read off various data output from the vehicle's tilt and telescopic ECU.
The tilt and telescopic ECU records the applicable DTCs when the computer detects a malfunction in the computer itself or its circuit.
To check the DTCs, connect a LEXUS hand-held tester to DLC3 on the vehicle. The LEXUS hand-held tester enables you to erase the DTCs and activate the several actuators and check freeze frame data and various forms on steering data.







b. DATA LINK CONNECTOR 3 (DLC3)
The tilt and telescopic ECU uses ISO 14230 for communication. The terminal arrangement of DLC3 complies with SAE J1962 and matches the ISO 14230 format.

HINT: If your display shows "UNABLE TO CONNECT TO VEHICLE" when you have connected the cable of LEXUS hand-held tester to DLC3, turned the ignition switch ON and operated the LEXUS hand-held tester, there is a problem on the vehicle side or tester side.

- If communication is normal when the tester is connected to another vehicle, inspect 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, so consult the service department listed in the tester's operator's manual.