The OBD2 code P0065 indicates a malfunction related to the Air Assisted Fuel Injection (AAI) system, which affects the air-to-fuel ratio entering the combustion chamber.
This system is designed to improve engine efficiency and reduce emissions by assisting in the atomization of the fuel, particularly during cold starts or low-load conditions. The code suggests there might be issues with the air assist injector solenoid, fuel injectors, or related components and circuits.
P0065 quick overview
| Meaning | P0065 – Air Assisted Fuel Injection (AAI) Control |
| Is it serious? | Yes, it can impact engine performance, fuel efficiency, and emissions. |
| Possible causes | – Malfunctioning air assist injector solenoid – Clogged or dirty fuel injectors – Faulty or damaged wiring and connectors in the AAI system – PCM issues not activating the solenoid properly |
| How to diagnose? | Inspect the AAI system for any blockages or leaks. Check the solenoid for proper operation and resistance levels. Examine the fuel injectors and fuel rail for any signs of blockages. Review electrical connections to ensure the PCM is activating the solenoid correctly. Consider a PCM reflash if the code persists, indicating potential software issues. |
P0065 Meaning
When you encounter a P0065 code, your car is telling you there’s a problem with the system that helps mix air with the fuel before it gets burned in the engine. This system helps make sure the fuel burns as efficiently as possible, which is good for both your car’s performance and the environment.
If something goes wrong here, you might notice your car running rough, using more gas than usual, or having trouble starting in cold weather. Fixing the issue could involve checking for clogs in the parts that deliver air to the fuel, making sure the electronics that control these parts are working right, or cleaning the fuel injectors to ensure they can spray fuel properly.
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How to fix P0065 – learn from mechanics
I looked into P0065 service cases at iatn.com website where in the private forums the mechanics seek advice from other mechanics. I looked up a bunch of cases to help you decide how to fix your issue and see what would a real mechanic do to solve it.
Case #1: Jaguar P0065
Vehicle information
2002 Jaguar S-Type 4.0L
Issue + repair history
- Initially diagnosed with P0065 code related to Air Assisted Fuel Injection (AAI) control.
- Checked AAI system for blockages or leaks, replaced valve under warranty.
- Code reappeared months later, cleared and suggested PCM reflash.
- Code returned despite PCM reflash. Replaced coils for cylinders 1, 5, and 8 based on history of misfires and P0065 occurrences.
Other OBD2 Codes + Test Results
- P0065 – Air assisted fuel injection (AAI) control.
- Mode $06 data showed misfire events for cylinders 8 and 1.
Mechanic suggestions
- Check if the car is running too lean as it may explain coil failures.
- Inspect fuel injectors and fuel rail for blockages.
- Review air control system, ensure air hoses are connected properly from idle air valve to injector fuel rail.
- If needed, remove fuel rail, remove fuel injectors, and visually inspect for dirt or blockages.
Final fix
Replaced coils for cylinders 1, 5, and 8.
Case #2: Subaru P0065
Vehicle information
2001 Subaru Forester L 2.5L
Issue + repair history
- Diagnosed with code P0065, air assist injector solenoid code.
- Solenoid regulates airflow to the base of air-assisted fuel injectors.
- Both hoses clear, valve works, but solenoid not being activated.
- Solenoid resistance: 21 ohms.
- Battery voltage on both wires, no ground supplied by PCM.
Other OBD2 Codes + Test Results
- P0065 – Air assist injector solenoid code.
Mechanic suggestions
- Check if the valve is sticking and not shutting off completely.
- Review service manuals for P0065 code, some may not list it.
- Check for clogged fuel injectors as suggested by some resources.
- Consider cleaning the injectors as a potential fix.
Final fix
Cleaned the injectors, and the issue seems to be resolved.
Case #3: Saturn P0065
Vehicle information
2002 Saturn Vue 3.0L
Issue + repair history
- Experienced code P0065 stored in BCM history only.
- Code does not recur in current data.
- No clear definition found for P0065, likely not a valid code.
- Light went off after driving, hasn’t returned since.
Other OBD2 Codes + Test Results
- Code: P0065 – No clear definition found.
Mechanic suggestions
- No clear guidance on the code’s meaning; may not be a valid code.
- Check for BCM or ECM issues if the code persists.
- Inspect wire harness for pinching or damage, as it may cause intermittent shorts.
Final fix
The issue resolved on its own after driving; no specific repair was performed.
How to diagnose P0065
I made you an overview of solving this DTC, based on all the advice that was suggested by certified mechanics to address this issue in previously mentioned service cases.
| Diagnostic Step | Explanation |
|---|---|
| Inspect the Air Assist Injector Solenoid | Check if the solenoid operates correctly and has the correct resistance. |
| Review Air Control System Connections | Ensure air hoses from the idle air valve to the injector fuel rail are connected and not leaking. |
| Check Fuel Injectors and Fuel Rail | Inspect for blockages or dirt that might impede fuel delivery. |
| Verify Solenoid Activation by PCM | Make sure the PCM provides the ground needed for solenoid activation, indicating electrical issues. |
| Consider Injector Cleaning | If clogged injectors are suspected, cleaning them may resolve the issue. |
Car Diagnostics Training
- Car Electrical basics
- OBD-II scanner basics
- How to use an OBD reader
- Introduction to a Bi-directional Scan tool
- OBD scanner buyer’s guide + discounts
I test OBD-II scanners and make DIY Engine diagnostics guides to help you solve your car problems without having to depend on the mechanic. A lot of them will try to scam you or are just no help at all. About Juraj Lukacko