P2431
AIR System Air Flow/Pressure Sensor Circuit Range/Performance Bank 1
Secondary air injection (emissions)
Generic OBD-II
Medium
What it means
P2431 means the secondary air injection system's airflow/pressure sensor is reading outside its expected range on bank 1. The secondary-air system pumps air into the exhaust at cold start to cut emissions, and this sensor confirms it's working. The fault is usually a bad sensor, a carbon-plugged passage, or a failed pump — it mostly affects emissions rather than everyday driving.
Medium
Can I keep driving? Usually drives normally; it mainly affects cold-start emissions, so it won't strand you but should be repaired to pass emissions.
Common symptoms
What you'll notice
- Check-engine light on
- Fails emissions testing
- Possible rough or slightly rich running right after a cold start
- Little or no change in normal driving
Common causes
Most likely first
- Faulty secondary-air airflow/pressure sensor reading out of rangeLikely
- Carbon-plugged or restricted secondary-air passagesCommon
- Failed air pump, air pump relay, or check valveCommon
- Leaking or disconnected secondary-air hoseLess often
- Sensor wiring or connector faultLess often
How to diagnose & fix
Work through it in order
- Scan live data for the secondary-air pressure/airflow sensor and compare with the pump on and off.
- Inspect the secondary-air hoses, check valve, and passages for leaks or carbon restriction.
- Verify the air pump runs when commanded on a cold start.
- Check the sensor connector and wiring for damage.
- Replace the sensor or clear the restriction as found, then clear and re-test.
FAQ
Quick answers
Is it safe to drive with P2431?+
Yes. The secondary-air system only runs briefly at cold start, so normal driving is unaffected. It will, however, fail an emissions test until repaired.
Can I just clear P2431?+
It returns after the next cold-start self-test. The sensor, pump, or restriction must be fixed for it to stay off.
Related codes
Often seen with P2431
Read & clear P2431 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