What does code P209B mean?

DTC codes / P20xx · Fuel and air metering and auxiliary emission controls / P209B

P209BReductant Injection Air Pressure Sensor B Circuit Range/Performance

P209B indicates that the powertrain control module has detected an out-of-range or performance fault in the reductant injection air pressure sensor B circuit, which monitors the air pressure used to help inject diesel exhaust fluid into the exhaust stream. The computer compares the sensor signal against expected values under specific operating conditions and flags the code when the signal falls outside the acceptable range or does not respond as expected.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering and auxiliary emission controls

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