P3449 Code: Cylinder 7 Deactivation/Intake Valve Control Circuit/Open

The cylinder deactivation system turns off certain cylinders in the engine when they are not needed to produce more power, such as idling or cruising. By decreasing the number of cylinders that need fuel sprayed into them, the system improves fuel efficiency and reduces emissions.

The engine control module (ECM) or powertrain control module (PCM) will log a P3449 code if the cylinder deactivation system on engine cylinder 7 has a problem.

What Does the P3449 Code Mean?

The diagnostic trouble code (DTC) P3449 indicates “Cylinder 7 Deactivation/Intake Valve Control Circuit/Open.” It applies to vehicles with engines that have eight or more cylinders.

Deactivation/intake valve control circuits are solenoids that can temporarily disable the intake valve in their respective cylinder. They are vital to the cylinder deactivation system, which allows the engine to run with fewer cylinders than it usually uses. For example, a V8 engine can run in V4 mode, which produces less power and saves fuel.

The ECM or PCM controls the engine’s 4-cylinder and 8-cylinder modes. It keeps track of the current load on the engine. When the engine load is light–such as when the vehicle is running idle or driving on a highway–the control will use the cylinder deactivation system to disable several cylinders.

The PCM regularly checks the deactivation/intake valve control circuits. If the controller determines that the intake valve for cylinder 7 isn’t working properly, it will set the generic powertrain diagnostic code P3449.

Note: The definition of code P3449 can differ according to the vehicle manufacturer. Check the appropriate repair manual or repair database for the exact code definition.

What are the Common Causes of the P3449 Code?

• Faulty cylinder deactivation solenoid
• Insufficient engine oil level or pressure
• Restricted oil passage
• Faulty or damaged wiring
• Corroded, damaged, or loose connector
• Bad ECM

What are the Common Symptoms of the P3449 Code?

• Engine misfire
• Higher fuel consumption and wastage
• Reduced engine performance
• Check engine light illuminated

How to Diagnose the P3449 Code

The P3449 code is a generic diagnostic code that various makes and models can log. Depending on factors like the vehicle’s year, make, model, and powertrain, the process to evaluate and repair the underlying issue can change between cases. There is no single solution to every case.

If you’re not confident about conducting diagnostic tests on your vehicle, it’s a good idea to bring it to a professional mechanic. Otherwise, you can go ahead and diagnose the issue yourself.

How to Fix the P3449 Code

Attempting to fix a P3449 code can become a challenging task if you don’t have the right tools and know-how to test the intake valves. In most cases, it’s best to leave the job to professionals.
For DIYers with advanced technical knowledge and hands-on experience who prefer to test and replace their vehicle’s faulty intake valve on their own, it will be helpful to rely on the appropriate repair manual or refer to an online repair database.