P0434
Heated Catalyst Temperature Below Threshold (Bank 2)
The heated catalyst on bank 2 has not reached its calibrated light-off temperature within the expected time after engine start. Heater element weak or insufficient supply.
- 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.
- Heater element ageingCommon
Parts involved
- Catalyst Heater
- Catalytic Converter
P0434 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.