P0065: Air Assisted Injector Control Range/Performance

What it means

The air-assist injector control system (used on some lean-burn or direct-injection engines to atomize fuel with air) shows a performance deviation from the expected behavior.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test

How it works

On engines equipped with air-assisted injection, the system directs air through passages at the injectors to help atomize fuel. The control module monitors the air-assist control system's response and sets P0065 when its operation falls outside the expected range or performance.

Common causes

Most likely first.

1. Air-assisted injector control valve or solenoid fault
2. Wiring or connector fault
3. Restricted air-assist passage

Symptoms

• Check-engine light on
• Rough idle
• Hesitation or reduced acceleration
• Engine may run poorly

How to diagnose it

1. Record freeze-frame data and note whether rough idle or hesitation occurred at a particular engine speed or load.
2. Check for related injector, air-assist, or mixture codes that could point to a shared control or airflow problem.
3. Inspect the air-assist control valve or solenoid connector and wiring for looseness, corrosion, or damage.
4. Check the air-assist passages and hoses for restrictions, leaks, or disconnection.
5. Test the control valve or solenoid response and circuit operation against the manufacturer's procedure.

Common fixes

• Reconnect or repair a loose, corroded, or damaged air-assist control connector or wire.
• Clear a restriction from the air-assist passage or hose.
• Replace a failed air-assist control valve or solenoid confirmed by testing.
• Repair a confirmed control-circuit fault.

Can I keep driving?

If the engine idles smoothly and accelerates normally, a short trip may be possible, but avoid hard acceleration if it hesitates or loses power. Continued poor air-assisted fuel atomization can worsen running quality and emissions.