P2197
O2 Sensor Signal Biased/Stuck Lean Bank 2 Sensor 1
Fuel & air metering (O2 sensor)
Generic OBD-II
Medium
What it means
P2197 means the upstream (sensor 1) oxygen sensor on bank 2 is reporting a signal that's biased or stuck lean — it isn't swinging the way the PCM expects. It can be the sensor itself failing, or a genuinely lean mixture from an intake/vacuum leak, exhaust leak, or fuel-delivery problem. The car usually still drives but may run rough and burn more fuel until it's diagnosed.
Medium
Can I keep driving? Usually drivable, but a stuck-lean signal can cause rough running and worse economy — fix it soon to avoid drivability and emissions issues.
Common symptoms
What you'll notice
- Check-engine light on
- Rough idle or running
- Engine surge or hesitation
- Reduced fuel economy
Common causes
Most likely first
- Faulty upstream (sensor 1) oxygen / air-fuel sensor on bank 2Likely
- An actual lean condition — vacuum/intake air leak on bank 2Common
- Exhaust leak upstream of the sensor drawing in airCommon
- Low fuel pressure or a weak/clogged injectorLess often
- Sensor wiring open/shorted or a poor connectionLess often
How to diagnose & fix
Work through it in order
- Read freeze-frame and live fuel-trim data to confirm whether the mixture is truly lean or the signal is stuck.
- Inspect bank 2 for intake/vacuum leaks and check for exhaust leaks near the sensor.
- Check fuel pressure and injector operation if trims show a real lean condition.
- Inspect the sensor's wiring and connector for corrosion or damage.
- If the mixture is correct but the signal stays stuck lean, replace the bank 2 sensor 1 O2 sensor.
FAQ
Quick answers
Is it safe to drive with P2197?+
Short-term usually, but running lean or rough wastes fuel and can raise emissions, so have it diagnosed soon.
Can I just clear P2197?+
It clears, but returns unless the underlying lean condition, wiring, or sensor is repaired.
Related codes
Often seen with P2197
Read & clear P2197 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