What does code U01AB mean?

DTC codes / U01xx · Lost communication with a control module / U01AB

U01ABLost Communication With Hybrid/EV Battery Interface Control Module L

U01AB is a generic network communication code indicating that one control module on the vehicle's data bus has stopped receiving messages from the Hybrid/EV Battery Interface Control Module L. The computer detected a loss of the periodic heartbeat or message set that this specific battery interface module is supposed to broadcast, so it flags the module as missing rather than reporting a fault inside the battery itself.

SystemNetwork

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyProfessional

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.