What does code U0165 mean?

Q: What does code U0165 mean?

Lost Communication With HVAC Control Module Rear. U0165 means the vehicle's main communication network has lost contact with the rear HVAC control module, which is the separate electronic unit that manages heating, ventilation, and air conditioning for the rear cabin area. The computer that stores this code has detected that no valid controller area network (CAN) messages are arriving from that module for a set period, so it flags the module as missing rather than reporting a specific fault inside the rear HVAC system.

DTC codes / U01xx · Lost communication with a control module / U0165

U0165Lost Communication With HVAC Control Module Rear

U0165 means the vehicle's main communication network has lost contact with the rear HVAC control module, which is the separate electronic unit that manages heating, ventilation, and air conditioning for the rear cabin area. The computer that stores this code has detected that no valid controller area network (CAN) messages are arriving from that module for a set period, so it flags the module as missing rather than reporting a specific fault inside the rear HVAC system.

SystemNetwork

Code typeGeneric (all makes)

SeverityLow

Fix difficultyIntermediate

AreaLost communication with a control module

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.