O2 Sensor Reference Voltage Circuit Low Bank 1 Sensor 1
What it means
P2245 means the reference voltage the PCM supplies to the bank 1, sensor 1 wideband air-fuel (oxygen) sensor has dropped too low. That reference is what the sensor needs to report the exhaust mixture back to the computer, so a fault can push the engine into open-loop fueling — worse economy and sometimes rougher running. This is an electrical circuit code, so the causes are the sensor itself or its wiring and connector, not fuel pressure or intake leaks.
Can I keep driving? Drivable — but this upstream sensor helps control the fuel mixture, so expect worse economy and possibly rougher running until it's fixed.
Common symptoms
What you'll notice
- Check-engine light on
- Poor fuel economy
- Possible rough idle or hesitation
- May fail an emissions test
Common causes
Most likely first
- Faulty wideband air-fuel (O2) sensor, bank 1 sensor 1Likely
- Open, shorted, or high-resistance reference-voltage wiringCommon
- Poor or corroded connector at the sensorCommon
- Faulty PCM reference supply (least likely)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and check for companion O2/air-fuel sensor codes.
- Inspect the bank 1, sensor 1 connector and wiring for opens, shorts, and corrosion.
- Measure the reference voltage and ground at the sensor; a 'circuit low' fault means the reference is being pulled down or lost.
- Test the air-fuel sensor for correct operation.
- Replace the air-fuel (O2) sensor if the reference fault is internal. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P2245?+
Can I just clear P2245?+
Related codes
Often seen with P2245
Read & clear P2245 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.