P2ABFIntake Air O2 Sensor Reference Voltage Circuit/Open Bank 1
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P2ABF points to an open circuit in the reference voltage line of the intake air oxygen sensor on bank 1. This sensor is a wide-band element placed in the intake tract, usually before the intercooler, that measures how much oxygen the incoming charge still contains and therefore how much exhaust has been recirculated. Ford's patent US8775011B2 describes it as a UEGO-type sensor that delivers either a pumping current or a voltage; a related Ford application reads the pumping current while a reference voltage is applied. With the reference lead broken, that loop cannot work and EGR control loses its feedback. No manufacturer documents P2ABF publicly; under CARB rules every engine input must be monitored for broken circuits. P2AC0 is the plausibility fault, P2AC1/P2AC2 low/high, P2AC3 bank 2.
- What you may notice
- Check engine light on
- EGR runs without sensor feedback or is reduced, higher NOx emissions
- Likely causes
- LikelyBroken reference wire or pushed-back pin between sensor and ECM
- PossibleCorroded or loose sensor connector in the damp intake area
- RareSensing cell of the intake oxygen sensor internally open
- 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: €0 – €350
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.