DTC U1004: Lost Communication with Engine Gateway Module [09/2015 - ]: Description

The ECM stores this DTC when no signals can be received from the ECUs that have been memorized as those connected to the braking and driving bus.
When the ECM receives a response signal from the ECUs connected to the braking and driving bus, the ECM recognizes and memorizes that the ECU is connected to the braking and driving bus. Based on this memorized data, the ECM monitors for malfunctions in the ECUs connected to the braking and driving bus when communicating with those ECUs. If the ECM cannot receive response signals from the ECUs that have been memorized as those connected to the braking and driving bus, the ECM 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
U1004	Lost communication with engine gateway module	Braking and driving bus circuit Parking brake ECU assembly CAN main wire or connector Blind spot monitor sensor LH CAN branch wire or connector1 Skid control ECU assembly CAN branch wire or connector ECM CAN branch wire or connector Driving support ECU assembly CAN branch wire or connector2 Steering control ECU CAN branch wire or connector3 Suspension control ECU CAN branch wire or connector4 Clearance warning ECU assembly CAN branch wire or connector Power steering ECU assembly CAN main wire or connector Parking brake ECU assembly Blind spot monitor sensor LH1 Skid control ECU assembly ECM Driving support ECU assembly2 Steering control ECU CAN branch wire or connector3 Suspension control ECU4 Clearance warning ECU assembly Power steering ECU assembly No. 4 junction connector No. 6 junction connector No. 7 junction connector