OBD-II code · Powertrain (generic)
P0430 Catalyst System Efficiency Below Threshold (Bank 2)
Same condition as P0420 but on bank 2. On engines with one shared catalyst per bank, P0420 and P0430 appearing together usually point to age rather than damage.
Is it safe to drive with P0430?
Usually safe for short trips, but don’t ignore it: the underlying fault can get more expensive over time.
Common causes
- Most likelyCatalyst aged or contaminated
- PossibleDownstream oxygen sensor drift
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
- 1.5–5 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Catalytic Converter, Oxygen Sensor Upstream, Oxygen Sensor Downstream
Related codes
- P0420Catalyst System Efficiency Below Threshold (Bank 1)
- P042DCatalyst Temperature Sensor Circuit High (Bank 1 Sensor 2)
- P042EEGR A Control Stuck Open
- P042FEGR A Control Stuck Closed
- P0431Warm Up Catalyst Efficiency Below Threshold (Bank 2)
- P0432Main Catalyst Efficiency Below Threshold (Bank 2)
- P0433Heated Catalyst Efficiency Below Threshold (Bank 2)
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.