P02B1
Cylinder 6 - Injector Leaking.
- Generic
- Powertrain
- Generic code
- High severity
How this code is built
- P
- SystemPowertrain
- 0
- Defined bySAE, the same on every car
- 2
- AreaFuel and air metering (injector circuit)
- B1
- FaultThe specific fault in that area
What it means
P02B1 means the engine control unit has detected that the fuel injector on cylinder 6 is leaking, allowing fuel to enter the cylinder when it should be closed. The ECU usually infers this from fuel trim, fuel rail pressure decay or misfire behaviour for that cylinder. The exact detection method and conditions vary by manufacturer and engine.
Symptoms
- Hard or long cranking when starting, especially when hot
- Rough idle or misfire on cylinder 6
- Smell of fuel from the exhaust or engine bay
- Engine management light on, possibly flashing if misfire is severe
- Poor fuel economy
- Fuel dilution of the engine oil, which may show as a rising oil level or fuel smell on the dipstick
Possible causes
- Leaking or sticking cylinder 6 fuel injector (worn seat, carbon or debris preventing it closing)likely
- Injector internal fault or electrical drive fault causing it to stay partially openpossible
- Fuel rail pressure too high due to a faulty pressure regulator or pressure control valve (engine dependent)possible
- Damaged or poorly seated injector seals or washers allowing fuel or pressure loss at cylinder 6possible
- Wiring or connector fault on the cylinder 6 injector circuit giving incorrect operationrare
- Outdated or faulty ECU calibration where a manufacturer bulletin lists this code as a known issuerare
How to diagnose
- Read all stored and pending codes and review freeze frame data, noting engine temperature, load and fuel trim values at the time the fault set
- Check for related codes such as misfires, fuel trim, fuel pressure or injector circuit faults, and check for any manufacturer bulletins for the model and engine
- Inspect the cylinder 6 injector connector and wiring for damage, corrosion, chafing or poor pin tension
- Look for external fuel leaks around the cylinder 6 injector, fuel rail and seals, and check the engine oil for fuel smell or a raised level
- Monitor fuel rail pressure with a scan tool at key-off and during start-up to see whether it drops abnormally fast or runs too high (procedure and specification vary by engine)
- Check live data for cylinder 6 misfire counts and fuel trims, and compare with other cylinders
- Perform an injector leak-down or balance test following the manufacturer procedure for the engine, or swap the cylinder 6 injector with another cylinder and see if the fault follows
- Check the spark plug for cylinder 6 for signs of being fuel-soaked or sooty
How to fix
- Replace the leaking cylinder 6 injector and fit new seals, washers or O-rings as the engine requires
- Repair or replace damaged wiring or connectors on the injector circuit
- Replace a faulty fuel pressure regulator or pressure control valve if rail pressure is out of specification
- Replace a fuel-soaked spark plug and change the engine oil and filter if fuel dilution is confirmed
- Update the ECU calibration only if a manufacturer bulletin identifies an outdated calibration as the cause
- Clear the codes after repair and road test to confirm the fault does not return
Can I keep driving?
High severity
Avoid driving until it is investigated, as a leaking injector can wash oil from the cylinder walls, dilute the engine oil and damage the engine or catalytic converter. If it must be moved, keep the journey very short and gentle.
Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.