P04B1
Refueling Vapor Control Valve Circuit Low
Generic OBD-II
Common symptoms
What you'll notice
- Check and replace the fuel cap
- Inspect and repair the wiring or connectors related to the refueling vapor control valve circuit
- Clean or replace the refueling vapor control valve
- Test and replace the fuel tank pressure sensor
Common causes
Most likely first
- Faulty refueling vapor control valve
- Loose or damaged wiring or connectors in the refueling vapor control valve circuit
- Malfunctioning fuel tank pressure sensor
- Clogged or blocked charcoal canister
- Damaged or leaking fuel filler cap
How to diagnose & fix
Work through it in order
- Check engine light illuminated on the dashboard
- Difficulty starting the vehicle
- Decreased fuel efficiency
- Rough idle or stalling
- Fuel odor present inside or outside the vehicle
Read & clear P04B1 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.