P2231
O2 Sensor Signal Circuit Shorted to Heater Circuit Bank 1 Sensor 1
Fuel & air metering (O2 sensor)
Generic OBD-II
Medium
What it means
P2231 means the signal wire of the bank 1, sensor 1 (upstream) oxygen sensor has shorted to its own heater circuit, so the ECM is getting a corrupted reading. Because this sensor guides fuel trim, a bad signal upsets the air-fuel mixture and can cause rough running and poor economy. It's most often chafed or heat-damaged wiring, a connector fault, or an internally shorted sensor.
Medium
Can I keep driving? Drivable, but a faulty upstream O2 sensor throws off fuel control, hurting economy and emissions and possibly causing rough running; repair soon.
Common symptoms
What you'll notice
- Check-engine light on
- Rough or uneven idle
- Increased fuel consumption
- Engine surge or hesitation
Common causes
Most likely first
- Faulty upstream oxygen sensor (bank 1, sensor 1)Likely
- Signal wire shorted to the heater circuit inside the harness or sensorCommon
- Chafed or melted wiring near hot exhaust bridging the two circuitsCommon
- Poor connection or corrosion at the O2 sensor connectorLess often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and note the O2 sensor's live signal behaviour.
- Inspect the O2 sensor wiring and connector for chafing, melting, or corrosion, especially where it routes near the exhaust.
- Check for a short between the signal and heater circuits with the connector unplugged.
- Repair or reroute damaged harness sections away from heat.
- Replace the upstream O2 sensor if wiring is good but the short is internal, then clear and re-test.
FAQ
Quick answers
Is it safe to drive with P2231?+
Yes for short trips — it won't strand you — but fuel control and emissions suffer while it's active, so repair it before long-term driving.
Can I just clear P2231?+
You can, but a signal-to-heater short from wiring or a bad sensor will bring it back until repaired.
Related codes
Often seen with P2231
Read & clear P2231 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