DTC U1002: Lost Communication with Gateway Module [09/2015 - ]: Description

The main body ECU (driver side junction block) stores this DTC when no signals can be received from the ECUs that have been memorized as those connected to the MS bus circuit.
When the main body ECU (driver side junction block) receives a response signal from the ECUs connected to the MS bus circuit, the main body ECU (driver side junction block) recognizes and memorizes that the ECU is connected to the MS bus circuit. Based on this memorized data, the main body ECU (driver side junction block) monitors for malfunctions in the ECUs connected to the MS bus circuit when communicating with those ECUs. If the main body ECU (driver side junction block) cannot receive response signals from the ECUs that have been memorized as those connected to the MS bus circuit, the main body ECU (driver side junction block) determines that a malfunction exists.
If 2 or more DTCs are output during the DTC check, one side of the CAN branch wire may be open (one side of the CANH [CAN branch wire]/CANL [CAN branch wire] of the ECU and/or sensor is open).

DTC Code	DTC Detection Condition	Trouble Area
U1002	Lost communication with gateway module (MS bus)	MS bus circuit Front multiplex network light ECU (front controller) CAN main wire or connector Front power seat switch LH CAN branch wire or connector Front power seat switch RH CAN branch wire or connector Front multiplex network door ECU LH CAN branch wire or connector Front multiplex network door ECU RH CAN branch wire or connector Rear multiplex network door ECU LH CAN branch wire or connector Rear multiplex network door ECU RH CAN branch wire or connector Tire pressure warning receiver assembly CAN branch wire or connector Main body ECU (driver side junction block) CAN branch wire or connector Certification ECU (smart key ECU assembly) CAN branch wire or connector Multiplex tilt and telescopic ECU CAN branch wire or connector No. 1 meter ECU sub-assembly CAN branch wire or connector Windshield wiper switch assembly CAN branch wire or connector Steering pad switch assembly (steering pad ECU) CAN branch wire or connector Outer mirror switch assembly CAN branch wire or connector Driving support ECU assembly CAN branch wire or connector1 Rear power seat switch CAN branch wire or connector2 Power trunk lid control ECU (luggage closer motor assembly) CAN branch wire or connector3 Luggage room junction block assembly (rear junction block ECU) CAN main wire or connector Front multiplex network light ECU (front controller) Front power seat switch LH Front power seat switch RH Front multiplex network door ECU LH Front multiplex network door ECU RH Rear multiplex network door ECU LH Rear multiplex network door ECU RH Tire pressure warning receiver assembly Main body ECU (driver side junction block) Certification ECU (smart key ECU assembly) Multiplex tilt and telescopic ECU No. 1 meter ECU sub-assembly Windshield wiper switch assembly Steering pad switch with modulator assembly (steering pad ECU) Spiral cable sub-assembly Outer mirror switch assembly Driving support ECU assembly1 Rear power seat switch2 Power trunk lid control ECU (luggage closer motor assembly)3 Luggage room junction block assembly (rear junction block ECU) No. 8 junction connector No. 9 junction connector No. 10 junction connector No. 11 junction connector No. 12 junction connector

*1: w/ Pre-collision System
*2: w/ Rear Power Seat Control System or Seat Heater System
*3: w/ Power Trunk Lid System