Error Code P0665 is defined as Intake Manifold Tuning Valve Control Circuit High Bank 2. This is a generic trouble code, meaning it applies to all vehicles equipped with the OBD-II system, particularly those made since 1996 up to present. This includes models from, but not limited to Acura, Chevrolet, Chrysler, Dodge, Ford, Honda, Isuzu, Land Rover, Mazda, Mitsubishi, Porsche, Saturn, Vauxhall, etc. Specifications on the definition, troubleshooting, and repairs, of course, vary from make, model, and powertrain configuration.

The PCM (powertrain control module, also known as ECM or engine control module in other vehicle makes) is responsible for monitoring and adjusting multiple sensors and systems involved in the operation of the vehicle. Including detects faults within said systems and circuits. One of these systems that the PCM is responsible is monitoring and correlating with desired values is the Intake Manifold Tuning Valve.

Commonly called the “flapper” valve, this piece comes up often in the repair world. The intake manifold tuning valve comes with many possible purposes to help the engine in both performance and drivability. It regulates the pressure between intake plenums, or redirect intake air to separate set of intake runners (or combination) to change the flow and possibly the performance of the engine. This valve is usually made of plastic, and with the notoriously high temperature inside the engine compartment, it’s common to see problems with this component.

Error Code P0665 is described as Intake Manifold Tuning Valve Control Circuit High Bank 2, meaning the PCM has detected an electrical reading on the valve bank #1 that is too high. Bank #2 refers to the side of the engine that does NOT contain the cylinder number 1.

This code is usually triggered by either mechanical or electrical fault with the intake manifold tuning valve. If you’re driving a vehicle in an area with susceptible extreme cold weather, this can cause the valve to malfunction and not rotate properly according to PCM’s desires.

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Common Symptoms

  • Poor engine performance
  • Reduced engine power
  • Possible misfire during startup
  • Altered power range
  • Increase in fuel consumption
  • Loud clicking noise coming from the engine bay
  • Cold start issues

Possible Causes

  • Loose control module ground strap
  • Defective fuel injector control module
  • Broken control module ground wire
  • Defective and malfunctioning CAN (Controller Area Network) bus or PCM
  • Damaged electrical components in PCM (or other CAN) bus
  • Defective PCM driver

How to Check

As with most codes, the first step in diagnosing this code is to check with the TSB (Technical Service Bulletins) and look for known issues with the specific vehicle.

Advanced diagnostic steps are usually vehicle specific, and require special advanced equipment and knowledge to accurately diagnose the problem. Below is the basic diagnostic step, but make sure you refer to the vehicle year, make, model, and powertrain configuration for the specific steps of your vehicle.

First Step

Start with clearing the codes to see if the error code comes back immediately. If it does NOT come back, take the vehicle for multiple test drives to see if it comes active again after a few drive cycles. If it does come back, then proceed with the diagnosis.

Second Step

Then, locate the intake manifold tuning valve. This can be tricky, as, in many models, they’re internally mounted in the intake manifold itself. With that said, the connector for the valve must be fairly accessible. Thus, check it and look for signs of damage such as broken tabs, melted plastics, etc. Also, make sure there is enough electrical connection.

Third Step

Depending on the capabilities of your scan tool or OBD code reader, you may be able to use it to operate the valve electronically. If this option is available for you, then you have a good way to check whether the valve is operating through its full range or not. Also, if you hear any clicking noises from the intake, then make sure to check the intake manifold tuning valve. If there is an abnormal clicking noise coming from the intake while you’re adjusting the sensor using the scanner, then you have an obstruction on your valve, or the valve itself may be stuck.

From here, you can proceed on removing the valve and check it thoroughly to look for signs of obstructions in the manifold. If you find no obstructions and clicking is still present, then you can try replacing the valve.

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Note that in some cases, this can be a difficult task, so make sure you research your vehicle beforehand and know the right parts and tool you can use.

Also, refer to the manufacturer’s technical data when performing diagnosis and repairs.

Fourth Step

Inspect the harness involved in the tuning valve. The wiring harnesses must be routed through the engine parts and other high heat areas. Not to mention engine vibrations can cause chafing and cracking.

Fifth Step

If you have done everything and the symptoms and problem still persist, then check the PCM, especially if there are multiple related codes present, or the problem is coming on and off intermittently.

How to Fix

Some of the most common repairs for this code include:

  • Reprogramming of the PCM
  • Updating PCM drivers
  • Replacement of faulty wires, connectors, and fuses
  • Replacement of ground straps, and ground wires
  • Replacement of fuel injector control module
  • Replacement of PCM or CAN Bus (rare)

The most common misdiagnosis of this code is a failure to follow the OBD-II diagnosis. Thus, it’s important to abide by the diagnosis and repairs step-by-step to ensure accurate and efficient repair.

Error Code P0665 may not be serious, but it can come with really annoying symptoms if left unattended for too long. If the problem is caused by a defective IMTV, then it can diminish the performance of the vehicle and increase fuel consumption.