Faulty or sticking air assisted injector or its air assist valve; Wiring or connector fault in the injector or air assist control circuit (open circuit, short, corrosion); Air supply problem to the assist system, such as a leak, blocked passage or restricted line; Carbon or fuel deposits restricting the injector tip or air passages; Incorrect fuel pressure or supply fault affecting injector performance; Fault in the engine control unit driver circuit or outdated calibration (model dependent).

P0065

Air Assisted Injector Control Range/Performance.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
0: AreaFuel and air metering, auxiliary emission controls
65: FaultThe specific fault in that area

What it means

P0065 is the generic code for Air Assisted Injector Control Range/Performance. The engine control unit has detected that the air assisted fuel injection system is not performing as commanded, for example air assist delivery, timing or injector operation falling outside expected limits. Air assisted injection is only fitted to a small number of engines, so the exact monitoring strategy depends on the model and engine.

Symptoms

Malfunction indicator lamp on
Rough idle or unstable running
Hesitation or poor throttle response
Hard starting, especially when cold
Increased fuel consumption
Poor fuel atomisation leading to misfire or higher exhaust smoke

Possible causes

Faulty or sticking air assisted injector or its air assist valvelikely
Wiring or connector fault in the injector or air assist control circuit (open circuit, short, corrosion)likely
Air supply problem to the assist system, such as a leak, blocked passage or restricted linepossible
Carbon or fuel deposits restricting the injector tip or air passagespossible
Incorrect fuel pressure or supply fault affecting injector performancepossible
Fault in the engine control unit driver circuit or outdated calibration (model dependent)rare

How to diagnose

Read all stored and pending codes and record the freeze frame data to see engine load, temperature and speed when the fault set
Check for related codes such as misfire, fuel trim or injector circuit faults, and deal with those first if present
Visually inspect the injector wiring, connectors and earths for damage, corrosion, chafing and water ingress
Inspect the air assist hoses, passages and connections for leaks, splits, blockages or loose fittings
Check live data for fuel trims and misfire counts to see if the problem is across all cylinders or just one
Test the injector and air assist valve circuits for supply, earth, signal and resistance against the manufacturer specification for that engine
Check fuel pressure against specification, as procedures and values depend on the model
Check for a technical bulletin or calibration update for the vehicle if no physical fault is found

How to fix

Repair or replace damaged wiring, terminals or connectors in the injector or air assist circuit
Replace the faulty air assisted injector or air assist valve
Repair air leaks and clear blocked or restricted air supply lines
Clean or replace injectors with deposit build-up, following the manufacturer's procedure
Correct fuel supply faults such as low pressure
Update the engine control unit calibration only if an outdated or faulty calibration is a known cause for that vehicle

Can I keep driving?

Medium severity

The car can usually be driven for a short time, but get it checked soon as poor fuel delivery may cause misfires, rough running and increased wear. If it runs very roughly or misfires heavily, limit driving to avoid damage.

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