P3401 code — how to fix error fast

Modern cars bring innovative technologies, and if you drive such a car, one of the most common OBD2 codes you may encounter is the P3401 code. It’s one of the possible reasons why your engine may not perform properly and that’s why it requires immediate response and an in-depth look into the P3401 code meaning.

Our team wanted to provide you with just that, so we created this guide with all the necessary information on the reasons why the code appears, and ways of finding the one behind it in your car to aid in fixing it.

Why you can trust REREV’s OBD2 code advice: Our automotive expert researchers with experienced mechanics undertakes a thorough research methodology to deliver precise insights on OBD codes. Find out more about OBD2 codes research process..

What does the P3401 code mean?

The P3401 code is a DTC that is related to the cylinder deactivation system in a vehicle’s engine. This system is designed to improve fuel efficiency by deactivating cylinders when they are not needed, such as when the vehicle is cruising at a constant speed.

When the system detects a problem with the cylinder deactivation system, it will throw the P3401 code. It is important to understand this code because it can indicate a serious problem with the engine that may lead to further damage if left untreated.

What causes the P3401 code?

The code P3401 can be caused by many things, but the most common culprit behind it is a faulty cylinder deactivation system of the engine. If your car has such a system, it may as well be the reason, but it’s not always the case, so here’s a complete overview of possible scenarios leading to the code:

Failed cylinder deactivation solenoid

One potential cause of the P3401 code is a failed cylinder deactivation solenoid. This solenoid is responsible for actuating the cylinder deactivation system, and if it fails, the system will not function properly. Symptoms of a failed solenoid may include rough idling, reduced fuel efficiency, and poor engine performance.

Malfunctioning cylinder deactivation system

Another potential cause of the P3401 code is a malfunctioning cylinder deactivation system. This can be caused by a variety of factors, including a faulty sensor, damaged wiring, or a failed actuator. Symptoms of a malfunctioning system may include engine misfires, reduced power output, and increased fuel consumption.

Low engine oil pressure

A third potential cause of the P3401 code is low engine oil pressure. The cylinder deactivation system relies on proper oil pressure to function, and if the oil pressure is too low, the system may not operate correctly. Symptoms of low engine oil pressure may include engine knocking, oil leaks, and reduced engine performance.

Which car models does the P3401 code affect the most?

All the car models with modern engines shut off some of the engine’s cylinders during low-load conditions to improve fuel efficiency can be affected by this code. Still, there are some car models that are known to be more prone to this code, so here’s a full list:

• Chevy Silverado: This full-size pickup truck is equipped with an Active Fuel Management (AFM) system that can deactivate up to four cylinders during light load conditions. However, some models have experienced issues with the CDS, resulting in the P3401 code being triggered.
• GMC Sierra: The Sierra is another full-size pickup truck from General Motors that uses the AFM system. Like the Silverado, some Sierra models have reported CDS-related issues that trigger the P3401 code.
• Honda Pilot: The Pilot is a mid-size SUV that also uses the VCM system. Some Pilot models have reported issues with the CDS, resulting in the P3401 code being triggered.

How to diagnose the P3401 code

Diagnosing the P3401 code requires the use of specialized diagnostic tools, such as an OBD-II scanner or a multimeter. The first step in diagnosing the code is to connect the diagnostic tool to the vehicle’s onboard computer and retrieve the code. Once the code has been retrieved, you can try one of the following methods for figuring out the exact cause:

Check for related codes

A code reader or scan tool can be used to read the P3401 code and any other related codes. This can provide a starting point for diagnosing the issue since it may also give you some more information about the problem if there are other codes associated with the P3401 code as well.

Perform a visual inspection

A visual inspection of the engine components can help identify any obvious issues, such as disconnected wires or damaged components.

Cylinder balance testing

A cylinder balance test involves disabling one cylinder at a time and measuring the change in engine RPM. This can help identify which cylinder is causing the issue.

Compression testing

A compression test measures the pressure inside each cylinder, which can help identify any issues with cylinder compression.

Performing an oil pressure test

An oil pressure test can help identify any issues with oil pressure, which is necessary for proper CDS operation.

How to fix the P3401 code

Fixing the P3401 code requires addressing the root cause of the problem. This may involve replacing a faulty cylinder deactivation solenoid, repairing damaged wiring, or performing other related repairs. Here’s a full list of the most common solutions to the code:

Repair the damaged wiring

If there is damage to the wiring or electrical connections related to the cylinder deactivation system, repairing or replacing those components may be required.

Clean or replace the lifters

Lifters are hydraulic actuators that are responsible for opening and closing the engine’s valves. If the cylinder deactivation system issue is related to lifter operation, cleaning or replacing them may be necessary.

Perform an oil change

The proper operation of the cylinder deactivation system depends on adequate oil pressure and flow. If oil pressure is low due to degraded oil, changing the oil may solve the problem.

How to prevent the P3401 code

Preventing the P3401 code requires proper maintenance of the cylinder deactivation system and the engine as a whole. This includes taking the following steps:

• Regularly replace engine oil
• Inspect the cylinder deactivation system from time to time
• Address any issues related to the ignition or cylinder deactivation system including damaged wiring

Additionally, it is important to follow the manufacturer’s recommended maintenance schedule for your vehicle to help prevent issues from occurring in the first place.

Our take

It’s pretty obvious that the code P3401 can arise for various reasons, so checking the cylinder deactivation system isn’t the only step you can take. However, it’s difficult to spot the true reason behind the code to an untrained eye, so our team was happy to help with some professional insight into diagnosing and removing the code.