Pre-Check

PRE-CHECK

1. MULTIPLEX COMMUNICATION SYSTEM (BEAN)
a. The BEAN communication line is divided into 3 circuits for the instrumental panel system, the door system and the lighting system. It is used for the air-conditioning and meter controls, etc., in the instrumental panel system, for the power window and door lock controls, etc., in the door system, and for the lighting, tilt and telescopic controls, etc., in the lighting system. Since all 3 circuits are connected in loop by the line, the line that is not open can maintain communication even if a part of the line becomes open for some reason. In case of the line becomes shorting (bus-down) for some reason, however, BEAN communication becomes impossible in the system and some diagnosis codes are output from the gateway ECU.

2. AVC-LAN SYSTEM
a. Separately from the above BEAN communication composed of 3 systems, there is the AVC-LAN communication line that is used for the audio system controls. If the communication line becomes open and short in part for some reason, DTC of the AVC-LAN communication impossible is output from the gateway ECU.

3. COMMUNICATION FUNCTION INSPECTION
a. Inspect battery voltage.
Standard: 10 - 14 V

b. Inspect diagnosis monitor code output.
1. Perform a diagnosis check of the gateway ECU by connecting the LEXUS hand-held tester to the DLC3 and turning the ignition switch ON

HINT:
- When diagnosis code check is impossible, check the following items.
- Display shows communication error (refer to new diagnostic system and operations when an error occurred.)

2. When the display shows diagnosis codes that the ECU unconnected and the communication bus defective, perform an inspection depending on the troubleshooting.

HINT: When other diagnosis code is output, refer to the diagnosis code table and the applicable section.