OBD-II code · Powertrain (generic, extended)
P20F2 SCR NOx Catalyst Efficiency Below Threshold (Bank 2)
SCR NOx Catalyst Efficiency Below Threshold (Bank 2): the control module has detected this fault condition.
Is it safe to drive with P20F2?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelySCR catalyst thermally aged
- PossibleCatalyst poisoning from sulphur or oil ash
Symptoms
- Check engine light on
- Failed emissions inspection
- Possibly slightly increased fuel consumption
- Sulfur (rotten egg) smell from exhaust under load
Repair at a glance
- Difficulty
- Hard
- DIY friendly
- Best left to a mechanic
- Typical labour
- 2–8 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Scr Catalyst, Nox Sensor Downstream
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.