What does code U049B mean?

Q: What does code U049B mean?

Invalid Data Received From Tachograph Module. U049B is a communication fault indicating that a control module received invalid or corrupted data from the tachograph module over the vehicle's network. The computer detected a message from the tachograph that failed its internal validity checks, such as a checksum error, out-of-range value, or missing expected data, so it flagged the signal as untrustworthy.

DTC codes / U04xx · Invalid data received from a module / U049B

U049BInvalid Data Received From Tachograph Module

U049B is a communication fault indicating that a control module received invalid or corrupted data from the tachograph module over the vehicle's network. The computer detected a message from the tachograph that failed its internal validity checks, such as a checksum error, out-of-range value, or missing expected data, so it flagged the signal as untrustworthy.

SystemNetwork

Code typeGeneric (all makes)

SeverityMedium

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.