Guide To P0066 OBD Error Code Solutions

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Is your Check Engine Light being illuminated? Is there slight stumble or hesitation from the engine when the throttle is released? Then, there might be the issue of OBD Code P0066 being flashed and stored in the PCM and the engine may go into fail safe mode to avoid any further damage.

On start up the engine reaches the optimal temperature for faster operation with the help of Air Assisted Injector. When the engine control module (PCM) detects an incorrect signal from the Air Assist Injector, it will set code P0066.

What causes problem of Air Assisted Injector Control Circuit or Circuit Low?

• Faulty or damaged wiring harness
• Vacuum leakage within injector or in hoses/clamps
• Defective/faulty Fuse/relay
• Air Assisted Fuel Injector faulty
• Rare ECM issue
• Pin/connector problematic

1. Engine Control Module - Faulty EVMs can also misinterpret the problem and point at wrong information leading to decreased performance. Replace faulty ECM components immediately.
2. Powertrain Control Module - If the PCM is faulty, it can cause major issues with Engine Control Module and the Transmission Control Module, thus hampering the performance. Thus, repair or replace faulty PCM components now!
3. Diagnostic Tool - In order to detect the error, one needs high grade diagnostic tools. Visit us today to grab amazing deals.
4. Air Assisted Injector System - This system if faulty will impact the fuel delivery system, thus impacting the engine output. Thus, a thorough check is in order and replace as necessary.
5. Air Assisted Fuel Injector - This injector if faulty, will impact the combustion process and the fuel delivery system, thus needs replacement. Buy now!
6. Throttle Body Assembly - In combination with the electronic throttle control system, the throttle body assembly is designed to control the amount of fresh air entering the engine. Thus, replace the faulty components immediately.

Common Symptoms

• Check Engine Light being illuminated
• Slight stumble or hesitation from the engine when the throttle is released
• Engine may die completely in very extreme cases

If the voltage to the air assisted injector system becomes too weak to open and close the air assisted injector control valve, the air/fuel mixture may be too rich temporarily during deceleration. This is what would cause the stumble and hesitation. The Check Engine Light illuminates due to this system being connected to the PCM.

P0066 code fixation would include:

• Replace faulty wiring or connectors associated with control circuit
• Replacement of Air Assisted Injector Valve
• Replacement of the vacuum hoses connected to the Air Assisted Injector Valve
• Replacement of one or more of the fuel injectors
• Replacing/Reprogramming faulty PCM

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• Begin your diagnosis by visually inspecting all wiring and connectors and look for shorted or burned wiring and replace circuitry and connectors. If the system wiring, connectors, and components appear to be in normal working order, connect the scanner to the diagnostic connector and record all stored trouble codes and freeze frame data.
• After the codes are cleared, operate the vehicle to see if the code returns. If the code fails to immediately return, you may have an intermittent condition. Intermittent conditions can prove to be quite a challenge to diagnose and in extreme cases may have to be allowed to worsen before a correct diagnosis can be made. Don’t forget to inspect vacuum hoses and mounting gaskets for discrepancies.
• Replace the damaged or corroded components and/or wiring/connectors as required. Check for voltage and ground signals at the air injection solenoid and compare your findings with manufacturer’s specifications
• Repair the circuits as necessary. If there is no voltage present, check system fuses and relays. If the ground is not present, look for loose or corroded ground straps and wires near the battery and engine block.
• Check solenoid operation as the solenoid is commanded with the scanner. If the solenoid electrical connector voltage is in line with manufacturer’s specifications, use the digital voltmeter to test solenoid resistance and compare your findings with manufacturer’s specifications and replace the solenoid if resistance levels don’t match with manufacturer’s specifications. If the solenoid, wiring, and connectors check out, perform a circuit resistance and continuity test.
• Replace faulty PCM if found. However, this issue is very rare.

Common mistakes when diagnosing the P0066 code

Common diagnostic mistakes that could be made during the repair of this issue could include replacing the fuel injectors or the air assisted injector valve without doing any proper diagnosis. Replacing any parts without first verifying that they are faulty would be a diagnostic mistake and is also very common and can easily cost more for repairs than it should as the problem might be elsewhere and can even be very tiny.

• Failed Powertrain Control Module (PCM)
• Failure of Throttle body assembly
• Wiring and control circuit connector issue