P0661 is a diagnostic trouble code (DTC) that is specific to Honda vehicles. It is a generic powertrain code, which means that it applies to all makes and models of Honda vehicles from the year 1996 onwards.
The P0661 code is related to the intake manifold runner control (IMRC) valve, which controls air flow through the intake manifold.
When the IMRC valve fails to function properly, it can trigger the P0661 code, indicating a problem with the valve’s circuitry or position sensor.
This code can cause various vehicle performance issues, including reduced power, poor fuel economy, and rough idling.
It is important to have this code diagnosed and repaired as soon as possible to prevent further damage to the engine and ensure optimal vehicle performance.
P0661 Honda Code – Intake Manifold Runner Control Valve Position Sensor Circuit Low Voltage
The diagnostic trouble code (DTC) P0661 refers to an intake manifold tuning valve control circuit issue. Your mechanic must diagnose the specific cause of your vehicle’s malfunction to determine why this code was triggered.
What Does the P0661 Honda Code Mean?
Typically, the P0661 code indicates that the PCM or another control module has detected a lower voltage from the intake manifold tuning valve control circuit than the automaker specifies.
Activating and closing the Intake Manifold Runner Control (IMRC) valve produces engine power. During low engine speed, high torque is achieved when the valve is closed. High torque and high engine speed are observed when the valve is open.
An Intake Manifold Runner Control (IMRC) valve position sensor is mounted on the valve shaft and detects the position of the IMRC valve.
Regarding the IMRC valve position when sliding on the board, the sensor includes a brush that moves with the valve, producing a linear signal response.
IMRC valve position sensor voltage, representing the IMRC valve position, is monitored by the Engine Control Module (ECM). The DTC is stored if the output voltage from the IMRC valve position sensor is higher than the set value.
Therefore, a P0661 code will be stored in the computer in the car if the PCM or another module detects that the voltage reading from the intake manifold tuning valve control circuit is low.
The code is monitored in self-tests conducted both with the key on/engine off and then with the key on/engine running. The code can take up to eight drive cycles to become active.
What Causes The P0661 Code?
You may encounter the P0661 code for a variety of reasons, including:
- Faulty fuel injector control module
- An open or short in the intake manifold tuning valve control circuit
- A loose connection within the circuit
- A bad driver in the PCM (likely)
- A faulty intake manifold tuning valve
What Are The Symptoms Of The P0661 Code?
It is possible to experience the following symptoms when you receive the P0661 code:
- Check Engine Light on
- Engine stalling
- Rough engine operation at idle
- Reduced fuel economy
- Reduced acceleration
How Does A Mechanic Diagnose The P0661 Code?
To diagnose the P0661 code, you use a handheld OBD II scanner to determine what codes are stored in your car’s computer. The mechanic will note those codes and clear them; then, the vehicle will be tested to determine if they are reset.
It is also necessary that the mechanic visually inspect all the wiring and connectors in the intake manifold tuning valve control circuit for opens, shorts, corrosion, or other damage. The most common issues are loose/poor connections or damage to the wiring harness.
In place of testing each individually, the mechanic should use an advanced scanner to determine the general area of the problem. Furthermore, a CAN scanner may be needed to isolate CAN bus malfunctions.
One of the most common causes of the P0661 code is a failed driver, so the mechanic should also check the PCM. Testing will also be required for the intake manifold tuning valve.
Test driving is required to determine the vehicle’s drivability and proper operation after the underlying problem has been diagnosed and repaired.
Basic Troubleshooting Steps
To troubleshoot a malfunction, the first step is to research Technical Service Bulletins (TSB) for the specific vehicle.
Diagnostic steps require advanced equipment and knowledge to be performed accurately and are often very vehicle specific.
Listed below are the basic steps for a repair, but for specific steps for your vehicle, please refer to the repair guide for your particular year, make, model, and powertrain.
Basic Step #1
A DIYer should always clear all diagnostic codes after a DTC (Diagnostic trouble code) is activated by the ECM to make sure it doesn’t return.
To test whether the vehicle becomes active again after a few duty cycles, drive it for a long time and numerous times.
Reactivate the code. If it does, diagnose the active code(s).
Basic Step #2
Your first step will be to locate the intake manifold tuning valve. Intake manifolds are usually installed internally, so this is difficult to accomplish.
Thus, inspect the connector for the valve visually for broken tabs, melted plastic, etc., if it is relatively accessible. Check that the electrical connection is adequate.
Basic Step #3
With this tool, you may be able to electronically operate the valve depending on its capabilities. This might be an effective way of determining if the valve is operating at its maximum capacity.
The intake manifold tuning valve can also be responsible for clicking noises coming from your intake, so it is a good idea to check it.
You likely have an obstruction in the intake, or the valve itself is stuck. If you hear abnormal clicking while adjusting the sensor with your scanner, there may be an obstruction.
The next step would be to remove and inspect the valve physically and inside the intake manifold for obstructions.
Replace the valve if there are no obstructions and there is clicking; this is probably the cause.
It can be challenging to work on these projects in some cases, so make sure you do your research before taking on the task so you won’t get stuck without the right parts, tools, etc.
Common Mistakes When Diagnosing The P0661 Code
This common mistake leads to addressing related symptom codes instead of the underlying issue.
An example would be a misfire code present, but that is not the actual problem, and fixing it will not correct the original cause of the code.
It is important that the mechanic starts with the earliest code and works forward until he reaches the latest to provide an accurate diagnosis.
How Serious Is The P0661 Code?
Depending on the specifics of your case, this may be nothing to be concerned about or something much more serious and damaging.
Tuning valves for intake manifolds are mechanical parts that can be rather complicated. Err on the side of caution when dealing with mechanical parts.
Please keep in mind that unwanted parts can enter the engine’s combustion chamber if you put off doing this.
Although P0661 is stored in your car, you may still be able to drive it. This code, however, can result in drivability issues in the future, so you must get it fixed immediately.
What Repairs Can Fix The P0661 Code?
The most common repairs for the P0661 code include the following:
- Reinstalling the driver in the PCM
- Replacing a failed intake manifold tuning valve
- Repairing loose or corroded connections in the wiring for the intake manifold tuning valve
Diagnosing the P0661 code can be challenging since there are many possible issues, and circuit/wiring testing alone can be time-consuming. To solve a problem, we need to diagnose the underlying cause rather than just change parts.
Although many things can cause the P0661 problem, the most common is that your Honda’s intake manifold tuning valve is faulty. Your vehicle needs to be diagnosed. Good luck!