P0424
Heated Catalyst Temperature Below Threshold (Bank 1)
The heated catalyst on bank 1 does not reach its target temperature within the expected time. Common causes are a defective heater element, supply fault, or a damaged temperature sensor.
- 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 open or shortedCommon
- Catalyst temperature sensor failedPossible
Parts involved
- Heated Catalyst
- Catalyst Heater
- Cat Temperature Sensor
P0424 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.