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P3408 is a diagnostic trouble code (DTC) for "Cylinder 1 Deactivation/Exhaust Valve Malfunction". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic for $70.00. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $30.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.
P3408 is the fault code for Cyl1 Exhaust Valve Ctrl Circ High. Cyl1 specifies that the issue is likely taking place in engine cylinder number 1.
Late model vehicles with eight or more cylinders are designed so that half of the cylinders deactivate, by way of the ECM (engine control module) disabling the fuel injectors. This deactivation conserves fuel economy under light load operating conditions when all cylinders aren’t needed. The ECM (engine control module) receives information about operating conditions from various sensors, like the MAF (mass airflow) sensor, and commands the cylinders on or off based upon that data. When the ECM receives a signal from these sensors that is not within the reference range, it will set a code alerting you to the situation – in this case a code that tells you the problem is happening at the exhaust valve of cylinder 1.
Cylinder deactivation can be affected by a number of problems, including:
On rare occasions, this problem may be caused by a faulty PCM or ECM, but this is typically not the case.
Cylinder deactivation malfunctions may cause the Check Engine light to come on. The vehicle will not be able to switch to V4 mode, and you may experience vibrations. If the issue is not addressed, you may notice a loss in fuel efficiency.
Steps that may be done to diagnose P3408 include:
The complete recommended diagnostic protocol should be carried out. If parts are replaced without testing all associated components, expensive, unnecessary repairs may result. Special attention should be paid to making sure the oil pressure is correct and cleaning out oil passages if it’s not.
This isn’t a code that will stop the vehicle from operating; however, over time additional damage could occur due to added stress on the engine from running in a way it wasn’t designed to run. It’s best to have a qualified mechanic assess the problem as soon as possible.
A cylinder 1 deactivation malfunction may involve one or more of the following repairs:
While your home scanner may give you a general idea of your vehicle’s problem, a qualified technician is equipped with tools that provide much more detailed information that can help in the diagnosis and repair of a cylinder deactivation circuit problem. The complex network of circuitry and sensors can make it difficult to pinpoint the issue without the proper tools and a considerable amount of time and effort. Consulting a professional can make the job faster and more efficient, and get your vehicle running smoothly and back on the road again.
YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.