What does code U0623 mean?

Q: What does code U0623 mean?

Lost Communication With Coolant Pump A. U0623 is a network communication fault indicating that a control module on the vehicle's Controller Area Network (CAN) bus has lost contact with the electric coolant pump designated as 'A'. The module that monitors the pump, typically the engine control module or a dedicated pump controller, has stopped receiving the periodic status messages the pump is supposed to broadcast, so it sets this code after a calibrated timeout.

DTC codes / U06xx · Network communication / U0623

U0623Lost Communication With Coolant Pump A

U0623 is a network communication fault indicating that a control module on the vehicle's Controller Area Network (CAN) bus has lost contact with the electric coolant pump designated as 'A'. The module that monitors the pump, typically the engine control module or a dedicated pump controller, has stopped receiving the periodic status messages the pump is supposed to broadcast, so it sets this code after a calibrated timeout.

SystemNetwork

Code typeGeneric (all makes)

SeverityMedium

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.