P01F1 code meaning
O2 Sensor Circuit Bank 1 Sensor 4
Powertrain system Generic code P01xx codes Check engine light
What P01F1 means
Sensor 4 on bank 1 is a fourth oxygen sensor, behind a third converter or converter brick. The OBD standard provides for up to four sensors per bank, and the code standard defines sensor 4 for bank 1 only. No manufacturer or vehicle using these codes could be identified; the description rests on CARB's requirements for downstream oxygen sensors and the logic of sensors 2 and 3. A switching sensor delivers about 0.1–0.9 V. P01F1 is the general circuit code of this sensor, the counterpart of P0136/P0142 for sensors 2 and 3. Typical causes are an aged sensor, open or high-resistance wiring and a failed heater.
P01F1 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyEasy, DIY possible
- Typical labor0.3 to 1.5 hours
- Clears after repairAfter a drive cycle
Symptoms of P01F1
- Check engine light on (usually after two drive cycles)
- Catalyst monitor readiness possibly not set
- Usually no change in driving
Common causes of P01F1
- Most likelySensor 4 aged or poisoned
- PossibleWiring or connector open, high-resistance or corroded
- PossibleSensor heater failed
- Less likelyControl module
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Oxygen sensor bank1 sensor4Oxygen sensor wiringCatalytic converter
What each part of P01F1 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 1 | Area: fuel and air metering. |
| F1 | The exact fault in that area. |
What to do next
- Note P01F1 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P01F1
What does P01F1 mean?
P01F1 means "O2 Sensor Circuit Bank 1 Sensor 4". Sensor 4 on bank 1 is a fourth oxygen sensor, behind a third converter or converter brick. It is a generic code, so it means the same on every make.
Is it safe to drive with P01F1?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P01F1 fail an emissions test?
Yes, it can. P01F1 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P01F1 to fix?
Difficulty: easy. A typical repair takes 0.3 to 1.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P01F1 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.