P3404
High voltage in cylinder 1 deactivation/intake valve control circuit
Generic OBD-II
Common symptoms
What you'll notice
- Check Engine Light will be ON
Common causes
Most likely first
- Low oil pressure
- Restricted oil passage
- Engine mechanical condition
- Faulty Cylinder Deactivation Solenoid
- Cylinder Deactivation Solenoid harness is open or shorted
- Cylinder Deactivation Solenoid circuit poor electrical connection
How to diagnose & fix
Work through it in order
- Replace MAF (Mass Air Flow) sensor after careful inspection of circuit
Read & clear P3404 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.