Cylinder 5 injector sticking open or leaking internally (worn or contaminated nozzle or seat); Damaged or worn injector seals or O-rings allowing fuel to seep past; Excess fuel rail pressure from a faulty pressure regulator or fuel pressure sensor, causing the injector to drip; Carbon or debris on the injector seat holding it slightly open; Wiring or connector fault at the cylinder 5 injector causing erratic operation; Fault in the engine control unit injector driver.

P02AD

Cylinder 5 - 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)
AD: FaultThe specific fault in that area

What it means

P02AD means the engine control unit has detected that the fuel injector on cylinder 5 is leaking, so fuel is getting into the cylinder when it should not. It is usually set when fuel trim, rail pressure decay or combustion monitoring shows that cylinder 5 is receiving more fuel than it has been commanded. The exact detection method depends on the model and engine.

Symptoms

Hard starting or long cranking, especially when hot
Rough idle or a misfire felt on cylinder 5
Smell of unburnt fuel from the exhaust
Black smoke or sooty exhaust
Poor fuel economy
Engine management light on, possibly with fuel trim or misfire codes

Possible causes

Cylinder 5 injector sticking open or leaking internally (worn or contaminated nozzle or seat)likely
Damaged or worn injector seals or O-rings allowing fuel to seep pastpossible
Excess fuel rail pressure from a faulty pressure regulator or fuel pressure sensor, causing the injector to drippossible
Carbon or debris on the injector seat holding it slightly openpossible
Wiring or connector fault at the cylinder 5 injector causing erratic operationrare
Fault in the engine control unit injector driverrare

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 of the fault
Check for related codes such as misfires, fuel trim or fuel pressure faults, as these may point to a wider fuel system problem
Inspect the cylinder 5 injector connector, wiring and earth for damage, corrosion or looseness
Check live fuel trims and misfire counters, comparing cylinder 5 with the other cylinders
Check fuel rail pressure against specification at idle and with the engine off, watching for pressure decay (procedure depends on the engine)
Inspect the cylinder 5 spark plug for fuel wetting, sooting or fouling compared with the others
Look for external fuel leaks and check the injector seals and O-rings for damage
Run an injector leak-down or balance test following the manufacturer's procedure for the engine

How to fix

Replace the leaking cylinder 5 injector and fit new seals, following the manufacturer's procedure
Replace damaged injector seals or O-rings if they are the source of the leak
Repair or replace a faulty fuel pressure regulator or pressure sensor if rail pressure is out of specification
Repair any damaged wiring or connectors at the injector
Replace a fouled spark plug and change the engine oil if it has been diluted with fuel
Have the engine control unit tested and replaced only if the driver fault is confirmed

Can I keep driving?

High severity

Limit driving and have it inspected promptly. A leaking injector can wash the cylinder walls, dilute the engine oil with fuel and overheat or damage the catalytic converter, and it is a potential fire risk if fuel is leaking externally.

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