P0424
Heated Catalyst Temperature Below Threshold Bank 1
Catalyst / emissions
Generic OBD-II
Medium
What it means
P0424 means the engine computer sees the bank 1 catalyst temperature staying below the level needed for the catalyst to work efficiently. It usually points to an aged converter, a faulty catalyst temperature sensor or wiring, or an exhaust leak letting the catalyst cool. It affects emissions rather than how the car drives.
Medium
Can I keep driving? Drivable — this is an emissions-monitor fault with no direct effect on how the car runs, but it will fail an emissions test until repaired.
Common symptoms
What you'll notice
- Check-engine light on
- Usually no noticeable driveability change
- May fail an emissions/smog test
- Possible slight drop in cold-start emissions performance
Common causes
Most likely first
- Aged or failing catalytic converter on bank 1 not reaching temperatureLikely
- Faulty catalyst temperature sensor or its wiringCommon
- Exhaust leak upstream of the catalyst letting it coolCommon
- Fault in the catalyst heater circuit (on heated-catalyst systems)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and check for exhaust leaks upstream of the catalyst on bank 1.
- Inspect the catalyst temperature sensor connector and wiring, and test the sensor's reading against actual temperature.
- On heated-catalyst systems, verify the heater circuit and its power/ground.
- If the sensor and wiring are good, evaluate the catalytic converter's condition. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0424?+
Yes — it's an emissions monitor fault that doesn't affect how the car drives. It should still be fixed to pass emissions testing and keep the catalyst working properly.
Can I just clear P0424?+
You can, but it returns after the monitor runs again until the underlying cause is repaired.
Related codes
Often seen with P0424
Read & clear P0424 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX