DTC U1002 (CAN MS BUS): Lost Communication with Gateway Module (Main body ECU): Description

WARNING: This page is about a different car, the 2011 Toyota Corolla. However, it is still accessible from the selected car via links, so may be relevant.

The main body ECU will store this DTC when no signals can be received from the ECUs that have been memorized as those that are connected to the CAN MS bus.
When the main body ECU receives a response signal from the ECUs connected to the CAN MS bus, the main body ECU recognizes and memorizes that the ECU is connected to the CAN MS bus. Based on this memorized data, the main body ECU monitors for malfunctions in the ECUs connected to the CAN MS bus when communicating with those ECUs. If the main body ECU cannot receive response signals from the ECUs that have been memorized as those connected to the CAN MS bus, the main body ECU determines that a malfunction exists.

DTC No.	DTC Detection Condition	Trouble Area
U1002	Main body ECU cannot receive signals from all ECUs that have been memorized as those connected to the CAN MS bus.	Open or short in CAN MS bus main wire or connector Open or short in CAN MS bus branch wire or connector Certification ECU Combination meter Main body ECU CAN No. 3 junction connector