P2250
O2 Sensor Reference Voltage Circuit High Bank 2 Sensor 1
Fuel & air metering
Generic OBD-II
Medium
What it means
P2250 means the PCM sees the reference voltage for the upstream wideband oxygen sensor on bank 2, sensor 1 reading too high. That reference is what the sensor's air-fuel measurement is compared against, so when it's out of range the ECM loses accurate feedback and fuel trim drifts, causing rough running and higher fuel use.
Medium
Can I keep driving? Driveable, but with the upstream sensor's reference off the ECM can't trim fuel accurately, so expect rougher running and higher consumption until it's fixed.
Common symptoms
What you'll notice
- Check-engine light on
- Rough idle or uneven running
- Higher fuel consumption
- Occasional engine surge or hesitation
Common causes
Most likely first
- Faulty upstream (bank 2, sensor 1) wideband/air-fuel oxygen sensorLikely
- Short to voltage or open in the O2 sensor reference-voltage circuitCommon
- Poor connector contact or corrosion at the sensor plugCommon
- Bad ground causing the reference voltage to read highLess often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and check for companion O2 reference codes (P2247, P2248, P2249).
- Inspect the bank 2 sensor 1 connector and wiring for corrosion, melting, and chafing near the exhaust.
- Check the reference-voltage circuit for a short-to-voltage or open, and verify the sensor ground against spec.
- Rule out intake or exhaust leaks near the sensor that can skew its operation.
- If the wiring and ground are good, replace the upstream oxygen sensor as specified.
FAQ
Quick answers
Is it safe to drive with P2250?+
Short trips are fine, but with the reference voltage out of range the ECM can't fine-tune fuel, so it runs less efficiently. Fix it before it wastes fuel or fouls the converter.
Can I just clear P2250?+
It returns once the ECM re-tests the reference circuit unless the wiring, ground, or sensor is repaired.
Related codes
Often seen with P2250
Read & clear P2250 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