Powertrain, generic · Fuel and air metering, auxiliary emission controls

P0065 Air Assisted Injector Control Range/Performance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

Air-assisted injectors have an air sleeve around the nozzle tip: air flowing past at high speed breaks the fuel spray into finer droplets, which improves combustion and cold starts and lowers hydrocarbon emissions. On port-injected engines this air is taken upstream of the throttle and dosed by a pulse-width modulated bypass solenoid; because it bypasses the throttle, it is part of the idle air. The system is rare and mainly found on older engines. P0065 means the control is electrically in order, but the effect is implausible. One documented method compares the idle speed controller correction with the air assistance switched on and off during stable idle; if the difference is too large, the code is set.

Likely causes

Air-assist solenoid sticking or dirty
Air hoses to the injectors leaking, disconnected or blocked
Air passages at the injectors coked
Air leak distorting idle control

Symptoms

  • Check engine light on
  • Rough or unstable idle
  • Poorer cold starting

Repair estimate

DifficultyMediumDIY possible
Parts and labour€50–300
Time1–2 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

air assisted injector solenoidair assist hosesfuel injectors

Related codes

P0066P0067P0505P0507

References: law.cornell.edu, patents.google.com, patents.google.com, patents.google.com.