P0433
Heated Catalyst Efficiency Below Threshold (Bank 2)
Heated (electrically warmed) catalyst on bank 2 fails efficiency monitoring. In addition to standard catalyst aging, faults in the catalyst heater control or supply can cause this code.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: hard
Symptoms
- Check engine light on
- Failed emissions inspection
- Possibly slightly increased fuel consumption
- Sulfur (rotten egg) smell from exhaust under load
Common causes
Ordered by how often each turns out to be the cause.
- Catalyst aged or contaminatedCommon
- Catalyst heater circuit faultPossible
Parts involved
- Heated Catalyst
- Catalyst Heater
- Oxygen Sensor Downstream
P0433 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.