P239FO2 Sensor Out of Range During Deceleration (Bank 2 Sensor 2) - Duplicate Listing of P2379
- 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
- P239F appears in code lists with the identical title already given to P2379: the post-catalyst oxygen sensor of bank 2 is out of range while the injectors are switched off on a closed throttle. Neither code has a published manufacturer application; the only documented member of this deceleration check is GM's bank 1 code P232F on the single-bank 2023 L5P diesel, so a second bank never occurs there. No source assigns P239F a separate meaning, which makes it a duplicate listing of P2379. If it is ever read out, the manufacturer's code text decides; diagnosis would follow the bank 2 rear sensor: look for exhaust leaks ahead of it, check wiring and compare its overrun reading with the front sensor. CARB requires such fuel-cut checks for rear sensors.
- What you may notice
- MIL on, engine runs normally
- Catalyst monitor may not complete
- Likely causes
- LikelyScan tool listing the duplicate number for a maker-specific fault
- PossibleAged rear oxygen sensor on bank 2
- RareAir leak in the bank 2 exhaust ahead of the sensor
- 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 – €300
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.