Hey guys, newbie here, just bought a 2012 Premium.


Can anyone tell me how these "active" engine mounts work? I find that when I'm coasting along and the CVT pins the engine rpms around 1500, the cabin resonates and I can feel it in my ears, almost like the engine vibration is travelling through the chassis. Anyone else notice this? Is it characteristic, or are the active mounts too soft???


Info / thoughts / advise ?

 

I have never eerienced what you are describing.

 

I don't hear it in my ears but I do feel the resonance you speak of. It's pretty bad the VQ is no longer any smoother than the QR 2.5.

 

The VQ does have a sort of odd exhaust boom at that rpm, but when I had my 2010, I was the only one that noticed because it really wasn't noticeable.

The variable engine mounts operate based on rpm. They are controlled by vacuum and engaged/disengage by solenoid controlled by the ECM. 1100rpm is the trigger point. If engine is below 1100rpm, mounts are soft and if over, they are hard. They are fluid-filled mounts, so I would look around at the mounts and see if you can tell bout anything leaking. Also worth checking vacuum lines and solenoids. Typically a simple resistance test would work and would expect it to test out around 5-15 ohms, but Nissan would be much more specific on what resistance values should be. You would have to consult the FSM to know for sure.

 

Do you think there is any risk to unplugging them and seeing if the symptom / frequency changes? Would they log a dtc and throw the MIL on?


Also, how much of a factor is the weather on them? As any rubber and oil will do, they harden / thicken up and I can imagine the mounts are much stiffer in cold weather restricting the flow in the mount. I'm in temps between 35F down to -15F right now...

 

The MIL only comes on when it is a fault that will affect emissions. O2 sensor, or cam position sensor or temperature sensors, etc. There are many, many codes that would fall into this category - but the engine mounts are not one of those.. The engine mounts won't affect emissions, so you will not get a light on the dashboard. However, there will be a fault code set in the ECM - nothing to be concerned about, though.

It is not going to hurt or damage anything to run the car with the engine mount solenoids disconnected. If i were you, I would try it and see if it made any difference.

Honestly, I can't remember / don't know if the solenoids are energized when soft or hard. You would really need a multimeter to check and see what the ECM is doing and someone else to lightly rev the engine while you check...

 

I see, so unplugged may default them soft, or stiff...


I'll see what the symptom does in the summer, for now, it's a heated seat and steering wheel that I care about, lol.


Thanks for your input, good info!