Air Assisted Injector Control Circuit Low
The P0066 code indicates a problem with the air assisted injector control circuit, specifically a low voltage condition. This circuit is part of the secondary air injection system, which helps reduce emissions by injecting air into the exhaust stream. A low voltage reading suggests a short to ground, open circuit, or faulty component in the circuit, potentially affecting engine performance and emissions.
01. Most Common Causes
- Faulty air assisted injector
- Open or shorted wiring in the control circuit
- Corroded or loose connector at the injector
- Failed engine control module (ECM)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Rough idle or hesitation during acceleration
- Increased emissions
- Possible poor fuel economy
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to confirm the code and check for related codes.
Step 2: Visually inspect the air assisted injector wiring and connector for damage or corrosion.
Step 3: Test the injector's resistance with a multimeter; compare to manufacturer specs.
Step 4: Check for voltage at the injector connector with the engine running; should be near battery voltage.
Step 5: If wiring and injector are good, test the ECM output signal; replace ECM if faulty.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as it can cause poor engine performance and increased emissions. You may experience rough idle or hesitation, which could be unsafe in traffic.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for diagnosis and repair, depending on the cause. Replacing the injector or repairing wiring is usually under $100, while ECM replacement can be more expensive.