What does code P22B9 mean?

DTC codes / P22xx · Fuel and air metering (injector circuits) / P22B9

P22B9O2 Sensor Positive Current Control Circuit Low (Bank 2 Sensor 2)

P22B9 indicates that the powertrain control module has detected an abnormally low current on the positive control circuit for the downstream oxygen sensor on bank 2, which monitors catalyst efficiency after the catalytic converter. The sensor's internal heater or signal circuit is not drawing the expected current, so the computer cannot trust the sensor's feedback for fuel trim and emissions control.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering (injector circuits)

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