P2272
O2 Sensor Signal Biased/Stuck Lean Bank 2 Sensor 2
Fuel & air metering (oxygen sensor)
Generic OBD-II
Medium
What it means
P2272 means the downstream oxygen sensor on bank 2 (after the catalytic converter) is reporting a signal stuck on the lean side instead of switching normally. It is most often a failing sensor, its wiring, or a small exhaust leak drawing in outside air. The car drives normally, but it will not pass an emissions test until the sensor reads correctly.
Medium
Can I keep driving? Yes — the car drives normally. This is the downstream sensor, so the main effect is a warning light and a likely emissions-test failure.
Common symptoms
What you'll notice
- Check-engine light on
- Fails an emissions/readiness test
- Possible slight increase in fuel consumption
- Often no noticeable change in how the car drives
Common causes
Most likely first
- Faulty downstream oxygen sensor (bank 2, sensor 2)Likely
- Open, shorted, or corroded wiring or connector at that sensorCommon
- Exhaust leak upstream of the rear sensor letting in outside airCommon
- Contaminated sensor from oil or coolant burning in the engineLess often
- Failed catalytic converter skewing the downstream reading, less likelyLess often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and confirm the code is bank 2, sensor 2 (the sensor after the converter on the bank opposite cylinder 1).
- Inspect the sensor's wiring and connector for damage, corrosion, or a loose pin.
- Check for exhaust leaks near the sensor and repair them first.
- Compare the sensor's live signal against a known-good sensor; replace it if it stays biased lean.
- Clear the code and re-test over a full drive cycle.
FAQ
Quick answers
Is it safe to drive with P2272?+
Yes — this is the downstream (post-catalyst) sensor, so it does not change how the engine runs. Fix it to pass emissions and keep fuel-trim accurate.
Can I just clear P2272?+
It will come back within a few drive cycles unless the sensor, its wiring, or a nearby exhaust leak is actually repaired.
Related codes
Often seen with P2272
Read & clear P2272 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX