DTC U1002: Lost Communication with Gateway Module (Main Body ECU) [09/2014 - 10/2015]: Description

The main body ECU (multiplex network 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 sub bus 1.
When the main body ECU (multiplex network body ECU) receives a response signal from the ECUs connected to sub bus 1, the main body ECU (multiplex network body ECU) recognizes and memorizes that the ECU is connected to sub bus 1. Based on this memorized data, the main body ECU (multiplex network body ECU) monitors for malfunctions in the ECUs connected to sub bus 1 when communicating with those ECUs. If the main body ECU (multiplex network body ECU) cannot receive response signals from the ECUs that have been memorized as those connected to sub bus 1, the main body ECU (multiplex network body ECU) determines that a malfunction exists.

DTC Code	DTC Detection Condition	Trouble Area
U1002	Main body ECU (multiplex network body ECU) cannot receive signals from all ECUs that have been memorized as those connected to sub bus 1.	Open or short in sub bus 1 main line or connector Open or short in sub bus 1 branch line or connector Main body ECU (multiplex network body ECU) Luggage closer motor assembly1 Front multiplex network door ECU LH Multiplex tilt and telescopic ECU Position control ECU assembly LH2 Power seat switch assembly3 Position control ECU assembly RH4 Front multiplex network door ECU RH Open or short in No. 3 junction connector Open or short in No. 5 junction connector Open or short in No. 6 junction connector Open or short in No. 11 junction connector