Multiplex Integrated Control System Description

Overview 

The body control module is one of the F-CAN and the B-CAN components. The body control module controls many systems related to the body controller area and security system, and also works as a gateway to diagnose the other B-CAN connected ECUs with the HDS.

Self-Diagnostic Function 

The body control module provides the self-diagnostic function - Refer to: Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode 1 and Test Mode 2 (without the HDS) or Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode B - Control Unit Not Communicating or Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode A - Initial Communication and DTC Checks for checking the communication and input systems.

Communication Check (Test Mode 1): 

When the B-CAN BUS or the connection to the gauge control module is disconnected, an error code is shown with the number of blinks of the interior lights, and the gauge control module displays the DTCs.

Switch Input Check (Test Mode 2): 

When the input of a switch or a sensor to the body control module has changed, diagnosis of the input system can be performed on the basis of the interior lights flashing count.

HDS Diagnostics 

The HDS connects to the data link connector (DLC) to communicate with the vehicle's control units. This allows the HDS to retrieve DTCs, diagnostic data, or transmit forced commands during output function tests.

Memory Customize Function 

The body control module has a feature that allows the settings of certain outputs to be customized to user preferences with the HDS.

Failsafe Function 

Hardware Failsafe Control 

When a CPU problem or an abnormal power supply voltage is detected, the body control module moves to the hardware failsafe mode, and each system output load is set to the pre-programmed failsafe value.

Software Failsafe Control 

When any of the data from the B-CAN cannot be received within a specified time, or an unusual combination of the data is recognized, the body control module moves to the software failsafe mode. The data that cannot be received is forced to a pre-programmed value.