U04xx fault codes: Invalid data

A control unit still receives the messages of another, but their content is implausible or corrupted. The unit that sends them is the first suspect, together with its supply.

How to read this code

The letter U names the system: Network. The next digit, 4, locates the fault: invalid data.

These codes are generic: they mean the same thing on every make. Some manufacturer tools display them with a two-digit suffix, such as P0101-00 or P010100: the suffix refines the fault type, and the base code keeps its meaning.

The codes of this family, part by part

Communication between control units

• U0401Invalid Data Received From ECM/PCM A
• U0402Invalid Data Received From Transmission Control Module
• U0415Invalid Data Received From Anti-Lock Brake System Control Module