What does code U0664 mean?

Q: What does code U0664 mean?

Lost Communication With Rear HVAC Air Cutoff Actuator. U0664 is a generic network communication code indicating that a control module on the vehicle's data bus has lost contact with the rear HVAC air cutoff actuator, which is the motorized door that stops airflow to the rear cabin vents. The module that monitors this actuator, typically the body control module or rear HVAC control module, has stopped receiving the expected response or status message from the actuator over the communication network.

DTC codes / U06xx · Network communication / U0664

U0664Lost Communication With Rear HVAC Air Cutoff Actuator

U0664 is a generic network communication code indicating that a control module on the vehicle's data bus has lost contact with the rear HVAC air cutoff actuator, which is the motorized door that stops airflow to the rear cabin vents. The module that monitors this actuator, typically the body control module or rear HVAC control module, has stopped receiving the expected response or status message from the actuator over the communication network.

SystemNetwork

Code typeGeneric (all makes)

SeverityLow

Fix difficultyIntermediate

AreaNetwork communication

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