P01F4
O2 Sensor Circuit Slow Response Bank 1 Sensor 4
Generic OBD-II
Common symptoms
What you'll notice
- Check and clean the O2 sensor connections
- Replace the O2 sensor
- Inspect and repair any damaged wiring or connectors in the O2 sensor circuit
- Check and clean the mass air flow (MAF) sensor
- Perform an engine tune
- up and replace any faulty spark plugs or ignition coils
Common causes
Most likely first
- Faulty oxygen sensor (Bank 1 Sensor 4)
- Dirty or contaminated oxygen sensor (Bank 1 Sensor 4)
- Damaged wiring or connectors related to oxygen sensor (Bank 1 Sensor 4)
- Engine vacuum leak
- Malfunctioning catalytic converter.
How to diagnose & fix
Work through it in order
- Poor fuel economy
- Decreased engine performance
- Rough idling or stalling
- Increased emissions
- Check Engine Light (CEL) illuminated on the dashboard
Read & clear P01F4 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.