When a +B short circuit or body ground short circuit is detected on the instrument panel system communication bus (BEAN), the instrument panel system communication bus (BEAN) is disabled and a DTC code is output.

Remove the H-LP LVL fuse from the main body ECU LH (cowl side J/B LH).

Remove the A/C fuse from the main body ECU LH (cowl side J/B LH).

Remove the FR DOOR RH fuse from the main body ECU RH (cowl side J/B RH).

If malfunction code is displayed during DTC check, check the circuit corresponding to the code in the table below. Proceed to the page given for the circuit.

Connect the intelligent tester to the DLC3.

The gateway ECU controls the functions of the multiplex communication system on the vehicle. Data of the multiplex communication system and the Diagnostic Trouble Codes (DTC) can be read through the Data Link Connector 3 (DLC3) of the vehicle.

Disconnect the gateway ECU connector.

Check for DTCs and note any codes that are output.

The LEXUS IS250 Multiplex Communication System (MPX) uses serial communication, which converts multiple pieces of information into serial communication data. As a result, they can be transmitted through a single communication wire.