Code result
P209B
Reductant Injection Air Pressure Sensor B Circuit Range/Performance
Moderate severity
What it means
The reductant injection air-pressure sensor B reads inside the electrical range but does not match expected behaviour over time or load — slow response or wrong offset.
Is it safe to drive?
Use caution
The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical.
Most likely causes
Sensor drift
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 mounting loose - signal damping
lowLess common, but worth ruling out after the more likely causes.
Related help
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