What does code U05A1 mean?

Q: What does code U05A1 mean?

NOx Sensor A Received Invalid Data From ECM/PCM. This code means the engine control module (ECM) or powertrain control module (PCM) has received data from the nitrogen oxide (NOx) sensor that it considers invalid or out of range. The ECM/PCM sets this code when the NOx sensor's signal does not match expected values or fails internal plausibility checks, indicating a communication or data integrity problem rather than a straightforward sensor failure.

DTC codes / U05xx · Network communication / U05A1

U05A1NOx Sensor A Received Invalid Data From ECM/PCM

This code means the engine control module (ECM) or powertrain control module (PCM) has received data from the nitrogen oxide (NOx) sensor that it considers invalid or out of range. The ECM/PCM sets this code when the NOx sensor's signal does not match expected values or fails internal plausibility checks, indicating a communication or data integrity problem rather than a straightforward sensor failure.

SystemNetwork

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaNetwork communication

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.