DTC U1002 Lost Communication with Gateway Module: Description

WARNING: This page is about a different car, the 2007 Lexus ES 350. However, it is still accessible from the selected car via links, so may be relevant.

The gateway 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 No. 2 bus.
When the gateway ECU receives response signals from the ECUs connected to the CAN No. 2 bus, the gateway ECU recognizes and memorizes that the ECUs are connected to the CAN No. 2 bus. Based on this memorized data, the gateway ECU monitors for malfunctions in the ECUs connected to the CAN No. 2 bus when communicating with those ECUs. If the gateway ECU cannot receive response signals from the ECUs that have been memorized as those connected to the CAN No. 2 bus, the gateway ECU determines that a malfunction exists.

DTC DETECTION CONDITION AND TROUBLE AREA

DTC No.	DTC Detection Condition	Trouble Area
U1002	Gateway ECU cannot receive signals from all ECUs that have been memorized as those connected to the CAN No. 2 bus.	Open or short in CAN No. 2 bus main wire Open or short in CAN No. 2 bus branch wire Wire harness or connector AFS ECU Distance control ECU Seat belt control ECU Gateway ECU CAN No. 1 J/C CAN No. 4 J/C