P2438
AIR System Air Flow/Pressure Sensor Circuit High Bank 2
Secondary air injection
Generic OBD-II
Low
What it means
P2438 means the engine computer detected high voltage in the bank 2 secondary air injection (AIR) flow/pressure sensor circuit. This system pushes air into the exhaust during cold starts to cut emissions, so the fault does not affect how the vehicle runs. The usual causes are the sensor, its wiring, or carbon-blocked air passages.
Low
Can I keep driving? Safe to drive. Secondary air injection mainly affects cold-start emissions, so the vehicle runs normally, but it may fail an emissions test.
Common symptoms
What you'll notice
- Check-engine light on
- No noticeable change in how the vehicle drives
- Occasional rough or higher idle right after a cold start
- May fail an emissions/readiness test
Common causes
Most likely first
- Failed secondary air (AIR) flow/pressure sensor on bank 2Likely
- Corroded or loose connector at the sensorCommon
- Signal wire shorted to voltage or an open in the circuitCommon
- Air passages or check valve restricted/plugged with carbonLess often
- Failed air pump or air control solenoid affecting the readingLess often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and inspect the bank 2 AIR flow/pressure sensor connector and wiring for a short to voltage or an open.
- Compare the sensor's live reading to spec with the air pump commanded on and off.
- Check the secondary air passages and check valve for carbon blockage.
- Verify the air pump and control solenoid operate correctly.
- Replace the sensor if it fails testing, then clear and re-test.
FAQ
Quick answers
Is it safe to drive with P2438?+
Yes. Secondary air injection is used mostly during cold starts for emissions, so it does not affect normal drivability. Repair it to clear the light and pass an emissions test.
Can I just clear P2438?+
It returns during the next cold-start test unless the sensor, wiring, or air system is repaired.
Related codes
Often seen with P2438
Read & clear P2438 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