Faulty or contaminated Bank 1 Sensor 4 oxygen sensor; Damaged wiring, poor connector contact or corrosion in the sensor circuit; Exhaust leak near the sensor affecting the reading; Genuine rich mixture from the engine, such as leaking injector, faulty fuel pressure regulation or related fuelling fault; Sensor contaminated by coolant, oil or silicone-based sealant; Fault in the control unit or its sensor supply or reference.

P01F7

O2 Sensor Signal Biased/Stuck Rich Bank 1 Sensor 4.

Generic
Powertrain
Generic code
Low severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
1: AreaFuel and air metering
F7: FaultThe specific fault in that area

What it means

P01F7 is a generic code meaning the oxygen sensor signal for Bank 1 Sensor 4 is biased or stuck rich. The control unit sees a voltage or reading from this sensor that stays on the rich side and does not respond as expected to changes in exhaust mixture. Sensor 4 is an additional downstream sensor, and its position depends on the exhaust layout of the model and engine, so check the manufacturer's data to identify it.

Symptoms

Engine warning light on
Little or no noticeable change in driving in many cases
Possible rich running, with higher fuel consumption
Smell of fuel or sooty exhaust if a real rich condition exists
Other fuel trim or catalyst efficiency codes stored alongside

Possible causes

Faulty or contaminated Bank 1 Sensor 4 oxygen sensorlikely
Damaged wiring, poor connector contact or corrosion in the sensor circuitlikely
Exhaust leak near the sensor affecting the readingpossible
Genuine rich mixture from the engine, such as leaking injector, faulty fuel pressure regulation or related fuelling faultpossible
Sensor contaminated by coolant, oil or silicone-based sealantpossible
Fault in the control unit or its sensor supply or referencerare

How to diagnose

Read all stored and pending codes and note the freeze frame data, including fuel trims, engine load and coolant temperature
Check for other fuelling, misfire or catalyst codes and deal with those first
Identify the location of Bank 1 Sensor 4 for this specific model and engine from manufacturer data
Inspect the sensor wiring, connector and terminals for damage, heat damage, water ingress or corrosion
Look for exhaust leaks around the sensor and upstream of it
View live data for the sensor and compare it with the other oxygen sensors on the same bank while the engine is warm
Check short and long term fuel trims for signs of a genuine rich condition, and check fuel pressure and injector condition if indicated
Check the sensor heater and supply circuits as per the manufacturer's procedure

How to fix

Repair or replace damaged wiring, connectors or terminals
Replace the Bank 1 Sensor 4 oxygen sensor if it is faulty or contaminated
Repair any exhaust leaks affecting the sensor reading
Correct the cause of any genuine rich running, such as a leaking injector or fuel pressure fault
Find and cure the source of any contamination, such as a coolant or oil leak, before fitting a new sensor
Clear the code after repair and road test to confirm it does not return

Can I keep driving?

Low severity

The car can usually be driven short term while you arrange a repair. If there are signs of real rich running, such as a strong fuel smell or poor running, get it checked sooner to avoid harming the catalytic converter.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.