P2198
O2 Sensor Signal Biased/Stuck Rich Bank 2 Sensor 1
Fuel & air metering (O2 sensor)
Generic OBD-II
Medium
What it means
P2198 means the upstream oxygen (air-fuel ratio) sensor on bank 2, sensor 1 is reporting a signal biased or stuck toward rich. That can be the sensor itself failing, or a real rich-running condition the sensor is correctly seeing. The engine stays drivable but may idle roughly and use more fuel, and prolonged rich running can harm the catalytic converter.
Medium
Can I keep driving? Drivable, but the mixture may be running rich — expect worse fuel economy and possible rough idle, and long-term rich running can shorten catalytic converter life.
Common symptoms
What you'll notice
- Check-engine light on
- Rough or uneven idle
- Increased fuel consumption
- Engine surging
Common causes
Most likely first
- Faulty upstream O2 / air-fuel ratio sensor (bank 2, sensor 1)Likely
- Sensor wiring open, shorted, or contaminatedCommon
- Poor or corroded connection at the sensorCommon
- Genuinely rich mixture — high fuel pressure or a leaking injectorLess often
- Exhaust or intake leak skewing the readingLess often
How to diagnose & fix
Work through it in order
- Read freeze-frame and view the bank 2 sensor 1 signal; a stuck-high/rich trace confirms the bias.
- Inspect the sensor connector and wiring for damage, corrosion, or exhaust contamination.
- Check fuel trims and fuel pressure to rule out an actual rich condition before condemning the sensor.
- Look for injector leakage and for intake/exhaust leaks near the sensor.
- If fueling is normal and wiring is good, replace the bank 2 sensor 1 O2/air-fuel sensor and retest.
FAQ
Quick answers
Is it safe to drive with P2198?+
Short term, yes. But a rich mixture wastes fuel and can overheat and damage the catalytic converter over time, so address it before long drives.
Can I just clear P2198?+
It returns until the sensor or the underlying rich condition is fixed, since the ECM keeps checking the bank 2 sensor's signal.
Related codes
Often seen with P2198
Read & clear P2198 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