What does code P22A4 mean?

Q: What does code P22A4 mean?

NOx Sensor Heater Control Circuit Low (Bank 1 Sensor 2). P22A4 means the engine computer has detected a low-voltage condition on the heater control circuit for the downstream nitrogen oxide (NOx) sensor on bank 1. The heater is not drawing the current the computer expects, so the sensor may not reach operating temperature and the system cannot accurately measure NOx levels.

DTC codes / P22xx · Fuel and air metering (injector circuits) / P22A4

P22A4NOx Sensor Heater Control Circuit Low (Bank 1 Sensor 2)

P22A4 means the engine computer has detected a low-voltage condition on the heater control circuit for the downstream nitrogen oxide (NOx) sensor on bank 1. The heater is not drawing the current the computer expects, so the sensor may not reach operating temperature and the system cannot accurately measure NOx levels.

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.