What does code U012F mean?

Q: What does code U012F mean?

Lost Communication With Generator B Control Module. U012F is a generic network communication code indicating that the engine control module (ECM) or another primary controller has lost the controller area network (CAN) signal from the generator B control module. The computer detected a complete absence of expected periodic messages from that module for a calibrated time window, not a charging system performance fault.

DTC codes / U01xx · Lost communication with a control module / U012F

U012FLost Communication With Generator B Control Module

U012F is a generic network communication code indicating that the engine control module (ECM) or another primary controller has lost the controller area network (CAN) signal from the generator B control module. The computer detected a complete absence of expected periodic messages from that module for a calibrated time window, not a charging system performance fault.

SystemNetwork

Code typeGeneric (all makes)

SeverityMedium

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.