Code result
P22F9
NOx Sensor Performance - Slow Response Low to High
High severity
What it means
NOx sensor on bank 1 sensor 1 responds too slowly when NOx concentration rises (typically observed when SCR dosing is reduced or stopped). The sensor has aged or its protection cap is clogged.
Is it safe to drive?
No — stop driving
This code points to a problem that can cause damage or affect safety. Avoid driving and have the vehicle diagnosed promptly.
Most likely causes
Sensor aged or protection cap clogged
highOne of the most commonly reported causes for this code — check this first.
Sensor element aged beyond calibration window
lowLess common, but worth ruling out after the more likely causes.
Sensor element contaminated by oil, soot or coolant
lowLess common, but worth ruling out after the more likely causes.
Related help
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