P2AF1Intake Air O2 Sensor Negative Current Control Circuit High Bank 2
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- How the car detects it
- P2AF1 is the high-side fault of the virtual-ground return on the bank 2 intake air oxygen sensor. Lifting this biased line towards supply voltage requires contact with a feed, most often the heater circuit in the same plug, or condensed water inside a connector. Once the return drifts up, the ECM can neither regulate the Nernst cell nor interpret the pump current, so the oxygen share of the bank 2 charge is lost. Ford's 2012 summary files a VM lead shorted to battery on its bank 2 exhaust probes as P0152; an intake sensor equivalent is not documented by any manufacturer, and CARB's comprehensive-component rule is the remaining basis. On a car that sets P2AF1, unplug the sensor and check the return pin against the Bosch pinout before replacing parts. P2AF0 is low, P2AEF open, P2AE8 bank 1.
- What you may notice
- Check engine light on
- EGR on bank 2 reduced, NOx may rise
- Likely causes
- LikelyReturn lead shorted to the heater circuit
- PossibleCondensed water inside a connector
- RareBias source in the ECM faulty
- 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.