AutoCodes – Generic – P0066

P0066 Code - Air Assisted Injector Control Circuit Or Circuit Low

Quick Answer

The Air Injection System supplies air to the Air Assisted Fuel Injectors using an Air Assist Injector Solenoid Valve. Common causes include Blocked or Clogged Inlet and Outlet Passages/Hoses, Faulty Air Assisted Injector Control Solenoid Valve, Air Assisted Injector Control Solenoid Valve harness is open or shorted. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P0066 indicates Air Assisted Injector Control Circuit Or Circuit Low.
Common causes: Common causes include Blocked or Clogged Inlet and Outlet Passages/Hoses, Faulty Air Assisted Injector Control Solenoid Valve, Air Assisted Injector Control Solenoid Valve harness is open or shorted.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 14,846

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jul 12, 2020

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
Comments
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Code P0066 Description

The Air Injection System supplies air to the Air Assisted Fuel Injectors using an Air Assist Injector Solenoid Valve. The Air Assist Injector Solenoid Valve supplies air to the Air Assisted Fuel Injectors in order to faster atomize the fuel and provide more efficient combustion. Not only does this improve engine driveability, but lowers vehicle emissions as well. The Diagnostic Trouble Code (DTC) sets when the Air Assist Injector Solenoid Valve has low input with two consecutive drive cycles.

OBDII Code P0066 - Air Assisted Injector Control Circuit Or Circuit Low - AutoCodes.com — P0066 Code - Air Assisted Injector Control Circuit Or Circuit Low

What does this mean?

What are the Possible Causes of the DTC P0066?

Blocked or Clogged Inlet and Outlet Passages/Hoses
Faulty Air Assisted Injector Control Solenoid Valve
Air Assisted Injector Control Solenoid Valve harness is open or shorted
Air Assisted Injector Control Solenoid Valve circuit poor electrical connection

How to Fix the DTC P0066?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

The fault could cause the engine to idle rough and possibly stall. The Air Assist Injector Solenoid Valve is supplied power from the main relay and controlled by the Engine Control Module. The Air Assist Injector Solenoid Valve can be tested by manually applying voltage and ground in order to actuate it. Once the valve is open, the air passages within the valve and system can be checked for obstructions. The Air Assist Injector Solenoid Valve can also be actuated by connecting the green test mode connector located under the instrument panel (On driver' s side, the connector is normally unplugged). Once connected, the Air Assist Injector Solenoid Valve will be turned on and off with the key placed in the on, engine off position. It will continue to turn on and off until the green test mode connector is disconnected.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0066 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P0066 code?

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Information for Specific Makes

P0066 Audi — Air Assisted Injector Control Circuit Or Circuit Low
P0066 Subaru — Air Assisted Injector Control Circuit Or Circuit Low
P0066 Volkswagen — Air Assisted Injector Control Circuit Or Circuit Low

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.