Code result
U05A2
NOx Sensor B Received Invalid Data From ECM/PCM
High severity
What it means
NOx sensor B (smart sensor with own ECU) received implausible data from the ECM/PCM. Engine load, fuel rate or temperature data needed for the sensor's internal compensation fails plausibility checks; the sensor reports degraded readings.
Is it safe to drive?
No — stop driving
This code can put the vehicle into limp or reduced-power mode. Avoid extended driving and have the vehicle diagnosed promptly.
Most likely causes
ECM/PCM internal fault or sensor input drift
highOne of the most commonly reported causes for this code — check this first.
Software version mismatch after replacement
mediumA plausible cause — test and verify before replacing parts.
Gateway module routing CAN messages incorrectly
lowLess common, but worth ruling out after the more likely causes.
Related help
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