O2 Sensor Negative Current Control Circuit Low Bank 2 Sensor 1
What it means
P2255 means the PCM detected a low reading on the negative current-control circuit of the bank 2, sensor 1 wideband air-fuel (oxygen) sensor. Modern wideband sensors use a pump-current circuit to measure the exhaust mixture, and a fault here degrades fuel control — typically worse economy and sometimes rougher running. Because it's an electrical circuit code, the causes are the sensor 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 2 sensor 1Likely
- Open, shorted, or high-resistance negative current-control wiringCommon
- Poor or corroded connector at the sensorCommon
- Faulty PCM current-control circuit (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 2, sensor 1 connector and wiring for opens, shorts, and corrosion.
- Measure the sensor's negative current-control circuit; a 'circuit low' fault means it's being pulled down or lost.
- Test the air-fuel sensor for correct operation.
- Replace the air-fuel (O2) sensor if the fault is internal. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P2255?+
Can I just clear P2255?+
Related codes
Often seen with P2255
Read & clear P2255 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.