P2255O2 Sensor Negative Current Control Circuit Low (Bank 2 Sensor 1)
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P2255 reports that the negative current control line (reference ground) of the bank 2 upstream wide-band sensor reads too low, typically a short to ground. No manufacturer publicly documents P2255 with thresholds. Ford's OBD summaries assign shorts to ground on any wide-band sensor line to P0151 and use P2254 only for an open line, and VW's 2014 specification books likewise list only P2254. The code therefore appears mainly where the sensor interface separates short-circuit faults by line. CARB requires circuit and out-of-range faults of fuel-control sensors to be detected and, where feasible, stored as separate codes. P2252 is the bank 1 counterpart, P2256 the high-side fault. Mixture control on bank 2 becomes unreliable.
- What you may notice
- Check engine light
- Higher fuel consumption
- Possible hesitation or uneven running
- Likely causes
- LikelyReference ground wire shorted to ground (chafed against exhaust or body)
- PossibleInternal fault in the wide-band sensor
- RareFault in the sensor interface of the ECM
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €80 – €400
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.