OBD-II code · Powertrain (generic)
P01F3 O2 Sensor Circuit High Voltage Bank 1 Sensor 4
Bank 1 sensor 4 O2 sensor signal voltage above expected range — short to power or sensor stuck high. A drifted or sluggish lambda sensor lets the mixture run lean or rich without correction — fuel economy and emissions suffer immediately.
Is it safe to drive with P01F3?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelySignal wire shorted to battery
- Less likelyConnector pins corroded - high contact resistance
- Less likelySupply wire pinched against B+ source
Symptoms
- Check engine light on
- Increased fuel consumption
- Possible rough idle or hesitation
- Failed emissions test
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.5–2 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Oxygen Sensor B1s4, Sensor Wiring
Related codes
- P01F0Coolant Temperature Relapsed Below Diagnostic Monitoring Temperature
- P01F1O2 Sensor Circuit Bank 1 Sensor 4
- P01F2O2 Sensor Circuit Low Voltage Bank 1 Sensor 4
- P01F4O2 Sensor Circuit Slow Response Bank 1 Sensor 4
- P01F5O2 Sensor Circuit No Activity Detected Bank 1 Sensor 4
- P01F6O2 Sensor Signal Biased/Stuck Lean Bank 1 Sensor 4
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.