Fuel and air

P0065 — Air Assisted Injector Control Range/Performance

Severity: medium Drive with care, to a shop

What P0065 means

P0065 means the engine control unit detected that the air assisted injector system is not performing as commanded. These systems mix pressurized air with fuel to improve atomization and are used on a small number of engines. The module compares its command to the system's response and sets the code and turns on the check engine light when the result is out of range.

Symptoms

  • Check engine light on
  • Rough or uneven idle
  • Hesitation or stumble when accelerating
  • Higher fuel consumption
  • Hard starting when cold
  • Reduced power under load
  • Possible misfires

Possible causes

  1. Faulty air assist control solenoid or valve
  2. Damaged wiring or corroded connector terminals
  3. Vacuum or air supply leak
  4. Faulty air assisted injector
  5. ECM software or calibration problem
  6. Related sensor fault or outside interference with the signal

How to diagnose

  1. Read freeze frame data and all other codes, especially misfire and fuel trim codes
  2. Inspect the connectors and harness to the solenoid and injectors for chafing, corrosion and oil
  3. Check fuel trims and mixture adaptation at idle and under load
  4. Inspect air and vacuum hoses and the intake tract for leaks or cracks
  5. Measure fuel pressure and compare it with the manufacturer's spec
  6. Test power and ground circuits at the solenoid and injectors and compare cylinder balance
  7. Command the solenoid or valve with a scan tool and check its response
  8. Check for an ECM software update for your model

Common fixes

  • Replace the faulty air assist solenoid or valve
  • Replace or clean the faulty injector
  • Repair damaged wiring and connectors
  • Fix air or vacuum leaks and replace damaged hoses
  • Reprogram or replace the ECM only after everything else is ruled out

Questions and answers

What does P0065 mean?

It's an air assisted injector control fault: the computer sees the system working outside its expected range. The usual culprits are the control valve, wiring or an air leak.

Can I drive with P0065?

Briefly and carefully, yes, but get it fixed soon. A wrong mixture hurts engine performance and can damage the catalytic converter.

How do I fix P0065?

Start by inspecting the wiring and checking the air lines for leaks, then test the solenoid and injectors. Replace the ECM last.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.