O2 Sensor Signal Biased/Stuck Lean Bank 1 Sensor 1
What it means
P2195 means the upstream oxygen (air/fuel) sensor on Bank 1 is reporting a persistently lean mixture and isn't switching normally. That can be a genuine lean condition — an intake or exhaust leak, low fuel pressure — or the sensor itself biased and stuck. The car usually still drives, but it may idle rough, surge, and use a little more fuel until the cause is found.
Can I keep driving? Usually drivable — the car may idle rough, surge, or use a bit more fuel, but it's not a code that strands you. Fix it before it worsens.
Real-world scan data
Appears alongside · share of P2195 scans
Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.
Common symptoms
What you'll notice
- Check-engine light on
- Rough idle or engine surge
- Slightly higher fuel consumption
- Occasional hesitation
Common causes
Most likely first
- Exhaust leak near the sensor drawing in fresh air (false lean signal)Likely
- Failed or aged upstream air/fuel (O2) sensor stuck on a lean readingCommon
- Genuine lean condition — vacuum/intake leak or low fuel pressureCommon
- Dirty or restricted fuel injectorsLess often
- Wiring or connector fault in the sensor circuitLess 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.
- Inspect for exhaust leaks near the upstream sensor and for intake/vacuum leaks.
- Check fuel pressure and injector condition if trims confirm a real lean condition.
- Inspect the sensor's wiring and connector, then replace the upstream O2/AF sensor if it stays biased lean.
- Clear the code and drive a full cycle to confirm the signal recovers.
FAQ
Quick answers
Is it safe to drive with P2195?+
Can I just clear P2195?+
Related codes
Read & clear P2195 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.