What does code P22A9 mean?

Q: What does code P22A9 mean?

NOx Sensor Heater Sense Circuit High (Bank 1 Sensor 2). P22A9 means the engine computer has detected an abnormally high voltage on the heater sense circuit for the downstream nitrogen oxide (NOx) sensor on bank 1. The sensor's heater is not drawing the expected current, so the computer flags the circuit as high and may disable NOx monitoring until the fault is repaired.

DTC codes / P22xx · Fuel and air metering (injector circuits) / P22A9

P22A9NOx Sensor Heater Sense Circuit High (Bank 1 Sensor 2)

P22A9 means the engine computer has detected an abnormally high voltage on the heater sense circuit for the downstream nitrogen oxide (NOx) sensor on bank 1. The sensor's heater is not drawing the expected current, so the computer flags the circuit as high and may disable NOx monitoring until the fault is repaired.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyProfessional

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.