P2233
O2 Sensor Signal Circuit Shorted to Heater Circuit Bank 1 Sensor 3
Oxygen sensor
Generic OBD-II
Low
What it means
P2233 sets when the signal wire of the third oxygen sensor on bank 1 is electrically shorted to that sensor's heater circuit, so the ECM can't read it correctly. Sensor 3 is a downstream monitoring sensor, so the car usually still runs normally — the fault is almost always a wiring short or a failed sensor.
Low
Can I keep driving? Safe to keep driving — sensor 3 is a downstream monitoring sensor, so the main effect is the warning light and emissions readiness rather than how the car runs.
Common symptoms
What you'll notice
- Check-engine light on
- Emissions readiness monitor won't complete
- Possible slightly rough running or minor economy loss
- May fail an emissions test
Common causes
Most likely first
- Signal wire shorted to the heater circuit in the harness or connectorLikely
- Faulty oxygen sensor (bank 1, sensor 3)Common
- Chafed or pinched wiring between the sensor and connectorCommon
- Corroded or damaged connectorLess often
How to diagnose & fix
Work through it in order
- Inspect the bank 1 sensor 3 wiring and connector for chafing or a signal-to-heater short.
- Confirm the sensor's signal and heater circuits are not shorted together.
- Repair any damaged wiring or connectors found.
- Replace the sensor if the short is internal to it.
- Clear and retest with a drive cycle.
FAQ
Quick answers
Is it safe to drive with P2233?+
Yes — this is a downstream monitoring sensor, so the car generally runs fine. The main downsides are the warning light and failing an emissions check.
Can I just clear P2233?+
It returns while the short is present; the wiring or sensor has to be repaired for the code to stay off.
Related codes
Often seen with P2233
Read & clear P2233 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