What does code U0646 mean?

Q: What does code U0646 mean?

Lost Communication With Motor Electronics Coolant Pump A. U0646 is a network communication code indicating that a control module on the vehicle's Controller Area Network (CAN) bus has lost contact with the motor electronics coolant pump A, which is an electrically driven pump used to circulate coolant through the engine and sometimes the hybrid or turbocharger circuits. The module that sets this code has detected that the pump's control module or the pump itself is no longer responding to messages on the communication bus, which may be due to a wiring fault, a failed pump, or a power supply issue.

DTC codes / U06xx · Network communication / U0646

U0646Lost Communication With Motor Electronics Coolant Pump A

U0646 is a network communication code indicating that a control module on the vehicle's Controller Area Network (CAN) bus has lost contact with the motor electronics coolant pump A, which is an electrically driven pump used to circulate coolant through the engine and sometimes the hybrid or turbocharger circuits. The module that sets this code has detected that the pump's control module or the pump itself is no longer responding to messages on the communication bus, which may be due to a wiring fault, a failed pump, or a power supply issue.

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.