Powertrain
generic / SAE
P0431
Warm Up Catalyst Efficiency Below Threshold (Bank 2)
The pre-cat (warm-up) catalyst on bank 2 has lost too much oxygen storage capacity. Its primary purpose — quickly reaching light-off after a cold start — is no longer met within the OBD limits.
SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number4 / 31
Possible causes
- Pre-catalyst aged or damaged high
- Oxygen sensor drift medium
Symptoms
- Check engine light on
- Failed emissions inspection
- Possibly slightly increased fuel consumption
- Sulfur (rotten egg) smell from exhaust under load
Inspection / repair
- Difficulty: hard
- DIY: shop recommended
- Estimated cost: 400–1800 €
- Estimated time: 1–4 h
- Component: warm up catalyst
- Component: oxygen sensor upstream
- Component: oxygen sensor downstream
- MIL / check engine light
- emissions-relevant
- drive cycle required
Sources
References
sae:J2012