OBD-II code · Powertrain (generic)
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.
Is it safe to drive with P0424?
Usually safe for short trips, but don’t ignore it: the underlying fault can get more expensive over time.
Common causes
- Most likelyHeater element open or shorted
- PossibleCatalyst temperature sensor failed
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
- 1–4 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Heated Catalyst, Catalyst Heater, Cat Temperature Sensor
Related codes
- P0423Heated Catalyst Efficiency Below Threshold (Bank 1)
- P0434Heated Catalyst Temperature Below Threshold (Bank 2)
- P0421Warm Up Catalyst Efficiency Below Threshold (Bank 1)
- P0422Main Catalyst Efficiency Below Threshold (Bank 1)
- P0425Catalyst Temperature Sensor (Bank 1, Sensor 1)
- P0426Catalyst Temperature Sensor Circuit Range/Performance (Bank 1 Sensor 1)
- P0427Catalyst Temperature Sensor Circuit Low (Bank 1 Sensor 1)
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.