P01BF

What it means

P01BF is a generic code meaning the Fuel Rail Pressure Sensor circuit for bank 2 has a range or performance problem. The engine control unit has compared the signal from the bank 2 rail pressure sensor with the pressure it expects, or with other data such as the bank 1 sensor or commanded pressure, and found it implausible. The exact sensor location and strategy depend on the engine, so check the manufacturer's information for your model.

Symptoms

• Engine warning light on
• Hesitation or poor acceleration
• Rough running or unstable idle
• Hard starting or long cranking
• Engine running in limp mode with reduced power
• Occasional stalling

Possible causes

• Faulty or drifting bank 2 fuel rail pressure sensorlikely
• Damaged wiring, poor connector contact or corrosion in the sensor circuit (signal, reference or earth)likely
• Real fuel pressure problem on bank 2 side, such as a weak or failing high pressure pump or low pressure supplypossible
• Leaking or sticking fuel pressure regulator, pressure control valve or injector affecting rail pressurepossible
• Restricted fuel filter or fuel supply fault causing low pressure at the railpossible
• Fault inside the engine control unit or outdated software calibration where the manufacturer has issued a fixrare

How to diagnose

1. Read all stored and pending codes and note the freeze frame data, including rail pressure, engine speed, load and temperature at the time of the fault.
2. Check for related fuel pressure, injector or other sensor codes, and check for any technical service bulletins for the model and engine.
3. Visually inspect the bank 2 sensor, its connector and wiring for damage, chafing, fuel contamination, corrosion or loose pins.
4. Check the sensor supply voltage, earth and signal wire for continuity and shorts, following the wiring diagram for the engine.
5. With a scan tool, compare actual and desired rail pressure on both banks at key on engine off, idle and under load, and compare the bank 1 and bank 2 sensor readings.
6. Check low pressure fuel supply pressure and fuel filter condition against the manufacturer's specification.
7. Test the high pressure pump, pressure regulator or control valve operation and check for injector leakage, using the procedure for that engine.
8. Check whether a software update is available for the engine control unit for this fault.

How to fix

• Replace the bank 2 fuel rail pressure sensor if it reads incorrectly compared with a known good reference.
• Repair or replace damaged wiring and clean or renew faulty connectors.
• Replace the fuel filter or repair the low pressure fuel supply fault if pressure is below specification.
• Replace a faulty pressure regulator, control valve or high pressure pump as confirmed by testing.
• Repair or replace leaking injectors if they are found to affect rail pressure.
• Update the engine control unit software only if the manufacturer lists an outdated calibration as a known cause.

Can I keep driving?

Nearby codes

• P01BEGenericFuel Rail Pressure Sensor Circuit Bank 2
• P01C0GenericFuel Rail Pressure Sensor Circuit Low Bank 2