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Error Code P0661 is defined as Intake Manifold Tuning Valve Control Circuit Low Bank 1. 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, 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 P0661 is described as Intake Manifold Tuning Valve Control Circuit Low Bank 1, meaning the PCM has detected a really low electrical reading is coming from the valve on bank #1. For vehicles with multiple bank engines (i.e., V6 and V8), bank #1 refers to the side of the engine that contains 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.
- 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
- Broken valve parts
- Stuck valve
- Defective intake manifold (runner) tuning valve
- Damaged electrical connector
- Wiring issues (chafed, corroded, cracked wires, etc.)
- Extreme cold
- Valve contamination
- PCM issues
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 diagnose the problem accurately. 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.
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 long test drives to see if it comes active again after a few drive cycles. If it does come back, then proceed with the diagnosis.
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.
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.
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.
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.
If you have done everything and the symptoms and problems 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
The most common fix of this code is the repair or replacement of bad wiring, connectors, and modules. Other common repairs include:
- Reinstalling the PCM driver
- Replacement of failed intake manifold tuning valve
- Repair of loose or corroded wiring connections in the intake manifold tuning valve
A misfire code may be present along with this code, but it may not be the actual problem. Attempting to fix the misfire code may alleviate the problem. For a more accurate diagnosis, mechanics should start with the earliest code and work forward up to the most recent. This is to avoid misdiagnosis, which usually results in a more serious problem.
This code results to drivability issues, thus, it’s important to have it addressed as soon as possible.