P2AC0Intake Air O2 Sensor Reference Voltage Circuit Range/Performance Bank 1
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- P2AC0 is set when the reference voltage circuit of the bank 1 intake air oxygen sensor is electrically present but behaves implausibly, for example drifting or not matching what the ECM expects for the current EGR and pressure state. Stellantis documents it explicitly for the 2.0L turbo four (sales code EC2) of the Alfa Romeo Giulia and Stelvio: TSB 18-067-22 REV. B for 2022 Giulia and TSB 18-041-23 REV. A for 2022 Stelvio both cure a lit MIL with P2AC0 by flashing new engine software, so a false detection rather than a worn part. The 2017 Giulia bulletin 18-030-17 already listed it next to P2B89. Ford's intake oxygen patents show that intake pressure and humidity shift the sensor output, which any plausibility check has to allow for. P2ABF is the open circuit, P2AC4 bank 2.
- What you may notice
- Check engine light on
- Usually no noticeable change in driveability
- Likely causes
- LikelyEngine software that detects the fault falsely (Stellantis reflash for Giulia/Stelvio 2.0L)
- PossibleIntake oxygen sensor aged or contaminated by oil mist from crankcase ventilation
- RareHigh resistance in the reference wire or connector
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Easy · Usually a job for a workshop.Typical cost: €0 – €350
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.