P0424 Code: Heated Catalyst Temperature Below Threshold (Bank 1)
🟠 Moderate severity · drivable
Drivable, but the heated catalytic converter isn't reaching working temperature and may need repair.
What P0424 means
The heated catalytic converter on bank 1 isn't reaching the temperature it needs to work. This usually points to the converter's electric heater element or its power circuit, not the converter itself.
Symptoms
- Check engine light is on
- Reduced fuel economy
- Possible failed emissions test
- Often no noticeable driving symptoms
Common causes
- most common: Faulty catalyst heater element
- common: Damaged heater wiring, fuse, or relay
- less common: Faulty temperature sensor
How to fix it
| Fix | DIY? | Typical cost |
|---|---|---|
| Check the heater fuse and relay | Yes | $0–60 |
| Repair heater wiring or replace the relay | Mechanic | $50–200 |
| Replace the heated catalytic converter | Mechanic | $600–2500 |
Frequently asked questions
Can I drive with a P0424 code?
Yes, but the heated converter isn't reaching working temperature. Get it diagnosed before your next emissions test.
What is the most common cause of P0424?
A faulty catalyst heater element or a problem in the heater's wiring, fuse, or relay.
How much does it cost to fix a P0424?
A fuse or relay is cheap; heater wiring repairs are $50–$200; a new heated converter is $600–$2,500.
Related codes
P0423
P0423 Code: Heated Catalyst Efficiency Below Threshold (Bank 1)
P0422P0422 Code: Catalyst 2 Efficiency Below Threshold (Bank 1)
P0420P0420 Code: Catalyst System Efficiency Below Threshold (Bank 1)
Updated 2026-08. This page is informational and not a substitute for professional diagnosis.