P01F1
O2 Sensor Circuit Bank 1 Sensor 4
Generic OBD-II
Common symptoms
What you'll notice
- Check and replace faulty O2 sensor
- Inspect and repair any damaged wiring or connectors related to the O2 sensor
- Clean or replace the Mass Air Flow (MAF) sensor
- Check for vacuum leaks and repair as necessary
- Perform an engine tune
- up, including checking and replacing spark plugs
Common causes
Most likely first
- Faulty O2 sensor in bank 1 sensor 4
- Wiring or connector issues in the O2 sensor circuit of bank 1 sensor 4
- Exhaust leak near bank 1 sensor 4
- Malfunctioning engine control module (ECM)
- Issues with the fuel injection system in bank 1 sensor 4
How to diagnose & fix
Work through it in order
- Check engine light illuminated
- Decreased fuel efficiency
- Rough idling or stalling
- Poor acceleration
- Increased emissions
Read & clear P01F1 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.