Code P0065: Air Assisted Injector Control Range Performance
What is code P0065?
The generic diagnostic trouble code (DTC) P0065 is a powertrain code that applies to vehicles equipped with an air assisted fuel injector. While present on various brands (Subaru, Jaguar, Chevy, Dodge, VW, Toyota, Honda), it primarily appears on Subaru and Jaguar models. Specific repair steps may vary by brand, model, and engine.
How the Air Assisted Injector Works
Similar to a conventional injector, the air assisted injector uses air to optimize fuel atomization during injection. This system is typically activated during cold starts, when the engine requires a richer air/fuel mixture. Uniform spraying is crucial, as a single injector mounted on the throttle body or intake often supplies multiple cylinders.
Cause and Triggering of the Code
The ECM (Engine Control Module) activates the check engine light and records code P0065 when it detects an anomaly in the air assisted injector circuit. This is usually an electrical issue, but an internal injector malfunction can also be the cause. This code is often associated with DTCs P0066 and P0067.
Severity of Code P0065
The severity is moderate. The code does not affect engine performance at normal operating temperature, but repeated cold starts with a too lean mixture can cause long-term damage. Therefore, repair is recommended.
Common Symptoms
- Hard starting in cold weather
- Exhaust smoke
- Poor cold performance
- Misfires
- Excessive fuel consumption
Possible Causes
- Damaged wiring harness
- Vacuum leak at the injector or pipes/clamps
- Faulty fuse or relay
- Defective air assisted injector
- ECM problem
- Corrosion or overheating of pins/connectors
Required Tools
- OBD-II code reader
- Multimeter
- Socket and wrench set
- Screwdriver
- Battery terminal cleaner
- Repair manual
Safety Tips
- Let the engine cool down before working
- Use wheel chocks to block the wheels
- Wear personal protective equipment (PPE)
Diagnostic Steps
1. Check Technical Service Bulletins (TSBs)
Check TSBs for your vehicle. A known fix may simplify diagnosis.
2. Inspect for Vacuum Leaks
Locate the injector (usually on the throttle body) by consulting the manual. Inspect pipes and seals for possible leaks. With the engine running, listen for abnormal hissing sounds. Use a vacuum gauge to measure intake vacuum and compare it to specifications.
Tip: Replace any cracked hoses to avoid future problems.
3. Electrical Test of the Injector
Measure the resistance at the injector terminals with a multimeter. Refer to the manual for reference values.
Caution: Use appropriate connectors to avoid damaging the pins.
4. Inspect Connectors
Check the injector’s electrical connector for corrosion or defects. Inspect the condition of the harness and its routing to avoid chafing.
Important: Always disconnect the battery before any electrical work.
5. Circuit Test
Test the continuity of the wires between the injector and the ECM with a multimeter. Perform a voltage drop test to check circuit integrity.
6. Real-World Condition Test
If your diagnostic tool allows, monitor the injector’s operation while driving to compare actual values with expected values.
Conclusion
Code P0065 indicates a problem with the air assisted injector. Although not critical, it requires investigation to avoid future complications. If the diagnostic steps exceed your skills, consult a professional mechanic for reliable repair.