P3459 code definition
The P349 code reflects that there is a problem with your vehicle’s TP, MAP, or MAF sensors.
What the P3459 code means
The control module in your vehicle is responsible for making sure that your ride is as safe, smooth and efficient as possible, even carrying out certain processes in service of this without letting you know.
One method of doing this is called cylinder deactivation mode. Basically, your vehicle is able to store a range of calculated values that would be enough to switch from V8 to V4 mode – again, without ever having to bother you.
The reason your vehicle does this is to increase fuel efficiency. Under light load conditions, your vehicle simply doesn’t need all eight cylinders – or all the gas they entail – to get the job done. So if the path ahead gets easier, special valve filters will stop intake and exhaust valves on certain cylinders from opening. All of this happens within milliseconds!
Unfortunately, sometimes, it should happen, but it doesn’t. When P3459 is stored, it’s because cylinders one and seven on the left bank and four and six on the right bank aren’t being shut down as they should, meaning your vehicle never enters V4 mode.
What causes the P3459 code?
There are actually a number of reasons that could contribute to the P3459 code being stored:
- A defective cylinder deactivation solenoid
- A cylinder deactivation solenoid harness is either open or shorted
- A cylinder deactivation solenoid circuit has incurred a poor electrical connection
- A problem with the engine’s mechanics
- Low oil pressure
- Something blocking the oil
What are the symptoms of the P3459 code?
There are really only a couple of symptoms that you may notice if your vehicle’s PCM has stored the P3459 code. First, you’ll probably see the Check Engine Light come on.
The other symptom you may take note of is that your vehicle’s fuel economy begins to suffer. This one is tough, though, because you may not use cylinder deactivation mode that much, meaning your fuel economy wouldn’t hurt by a lot either. However, by not being able to lay off extraneous cylinders, most of you will feel it at the pump a bit.
How does a mechanic diagnose the P3459 code?
A qualified mechanic will begin their diagnosis by using a scanner to confirm all the codes your PCM has stored. This will include the details regarding P3459. They’ll then inspect your vehicle’s cylinders and move onto the TP, MAF and MAF sensors. Your mechanic will also want to examine whether or not oil is able to transfer freely without issue.
Common mistakes when diagnosing the P3459 code
Again, one of the biggest mistakes with diagnosing the P3459 code is simply that it’s so easy to miss the problem in the first place. You may not even know it was a problem until you bring your vehicle in for some other reason.
This is why it’s a good idea to keep an eye on the MPG you generally get and take note if it begins changing unexpectedly. One possible explanation would be that your vehicle can’t shift to V4 mode when it would be prudent.
How serious is the P3459 code?
The problems related to the P3459 code definitely aren’t the kind that could damage your vehicle or put your life at risk. As we mentioned already, what it will do is end up costing you at the pump, so it’s probably worth having a professional fix it for you.
What repairs can fix the P3459 code?
Given that it’s a pretty simple problem, your mechanic shouldn’t have to do too much to fix it. They should only have to do one of the following:
- Reset the system
- Repair any malfunctioning sensors
- Fix or replace any electrical components that aren’t working (e.g. connectors, wires, etc.)
Additional comments for consideration regarding the P3459 code
The problems that cause P3459 should serve as a good reminder to always take your vehicle to a qualified mechanic when you see the Check Engine light, even if it seems like nothing is wrong.
Need help with a P3459 code?
YourMechanic can have a certified mobile mechanic to your home or office right away if your vehicle is suffering. Just call us at 1-800-701-6230 or complete our online form here and you’ll receive a free quote with your appointment.