The P0066: Air-Assisted Injector Control Circuit/Open refers to a problem within the control circuit for the air-assisted injector. This issue can stem from various causes, such as a wiring problem, a fault in the injector itself, or a failure in the Powertrain Control Module (PCM). In simple terms, when this code appears, it indicates that there is a disruption in the system responsible for managing the air-assisted injector’s function, which could impact the engine’s performance and emissions.
P0066 – Quick Overview
| Meaning | P0066: Air Assisted Injector Control Circuit/Open |
| Is it serious? | Yes, this code can be serious as it can affect the engine’s fuel delivery system, potentially leading to performance issues, increased emissions, and reduced fuel efficiency. |
| Possible causes | – Faulty air assisted injector – Open circuit in the control wiring – PCM (Powertrain Control Module) failure – Wiring or connector damage – Corrosion in connectors – Faulty relay controlling the injector |
| How to diagnose? | – Test the air assisted injector for proper operation. – Inspect the wiring and connectors for shorts or opens. – Check the PCM for faults and reprogram if necessary. – Verify electrical connections are secure. – Inspect for corrosion or damage in connectors. – Test the relay (if applicable) to ensure it is functioning properly. |
P0066 Meaning
The P0066: Air Assisted Injector Control Circuit/Open means there’s a problem with the part of your car that helps control how fuel is injected into the engine. This could be due to a wiring issue, a faulty injector, or a problem with the computer that manages the engine. When this code shows up, it suggests that something isn’t working right in the fuel system, which could affect how your car runs and how much fuel it uses.
Step-by-step diagnostic guide
Follow the outline procedure to diagnose this DTC by eliminating possible causes one by one.
| Action | Description | Tools Needed |
|---|---|---|
| Check for Other Codes | Use an OBD-II scanner to check if there are any other related codes present. These might give additional clues about the problem. | OBD-II Scanner |
| Inspect the Air Assisted Injector | Visually inspect the air assisted injector for any signs of damage, corrosion, or disconnection. Ensure it is securely attached. | Flashlight, Safety Gloves |
| Test the Air Assisted Injector | Using a multimeter, test the injector for proper resistance and operation. Compare the readings to the manufacturer’s specifications. | Multimeter, Manufacturer’s Specifications |
| Inspect Wiring and Connectors | Carefully check the wiring and connectors leading to the air assisted injector for any signs of wear, corrosion, or breaks. Look for loose or disconnected wires. | Flashlight, Multimeter |
| Repair or Replace Damaged Wiring/Connectors | If any wiring or connectors are damaged or corroded, repair or replace them. Ensure connections are secure and free from dirt or corrosion. | Wire Strippers, Electrical Tape, Replacement Wires/Connectors |
| Check the PCM (Powertrain Control Module) | Inspect the PCM and its connections for any signs of damage or loose connections. If the PCM is suspected to be faulty, it may need reprogramming or replacement. | OBD-II Scanner, Multimeter |
| Test the Relay (if applicable) | If your vehicle uses a relay for the air assisted injector, test the relay for proper operation. Replace it if it’s not functioning correctly. | Relay Tester, Replacement Relay |
| Clear the Code and Test Drive | After completing the necessary repairs, clear the P0066 code using the OBD-II scanner. Take the vehicle for a test drive to ensure the issue is resolved and the code does not return. | OBD-II Scanner, Vehicle Owner’s Manual |
| Recheck for Codes | After the test drive, re-scan the vehicle to ensure the P0066 code has not reappeared. If the code returns, further diagnosis may be required. | OBD-II Scanner |
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Hi, I am Juraj “Yuri” Lukacko. I got frustrated by unhelpful and scammy mechanics, so I decided to learn everything about car diagnostics myself. I test dozens of new car diagnostic tools every month along with learning new strategies to fix and customize cars. About Juraj Lukacko (Yuri)