What does code U04A4 mean?

Q: What does code U04A4 mean?

Invalid Data Received From Particulate Matter Sensor A. The engine control module (ECM) has lost the ability to trust the data stream coming from the particulate matter (PM) sensor, so it sets U04A4 to flag an invalid or missing message rather than a sensor performance fault. The computer is not saying the sensor is dead; it is saying the serial data it receives fails its validity checks, such as a missing checksum, out-of-range value, or a timeout on the dedicated communication line.

DTC codes / U04xx · Invalid data received from a module / U04A4

U04A4Invalid Data Received From Particulate Matter Sensor A

The engine control module (ECM) has lost the ability to trust the data stream coming from the particulate matter (PM) sensor, so it sets U04A4 to flag an invalid or missing message rather than a sensor performance fault. The computer is not saying the sensor is dead; it is saying the serial data it receives fails its validity checks, such as a missing checksum, out-of-range value, or a timeout on the dedicated communication line.

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.