What does code U0491 mean?

DTC codes / U04xx · Invalid data received from a module / U0491

U0491Invalid Data Received From Digital Disc Player/Changer Module D

U0491 is a communication fault where the engine control module or another network gateway has received data from the digital disc player or changer module that fails its internal validity check. The module is present and talking on the bus, but the content of its messages is corrupted, out of range, or missing expected parameters, so the receiving module flags the data as invalid rather than treating it as a lost connection.

SystemNetwork

Code typeGeneric (all makes)

SeverityLow

Fix difficultyIntermediate

AreaInvalid data received from a 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.