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There is a vibration on 2015 Sienna when engine speed at around 1250 RPM. Some vehicles are very minor, and others could be very severe. The vibration on my 2015 Sienna sometimes was very severe and along with the lower frequency drone noise. This had made me feeling very headache and ears pain. Had brought it to the dealer several times for a inspection. Nothing found! Had test another brand new 2015 Sienna SE, did the same thing, just a little better than mine. The last time I went to the dealer, they did something on the CAT converter. Before, there were four lock washer on the 4 bolts (with spring on it) those connects the CAT converter to the front and rear manifold pipe. The service tech removed those lock washers and tightened the four bolts. Because they believed that the vibration was caused by the looseness of those joins. But after I picked up my Sienna , I found the vibration was worse than before. Then I was thinking if I made it a little looser, would it be a little better?? So what I did is put 2 flat washer and 1 lock washer on each bolt. After I tightened those bolts, the spring on it will only be compressed 1 to 2 turns. I test drove my Sienna after doing this. The vibration almost went away. There is only minor vibration when cold start the car. Those drone noise also is not noticeable. If you are experiencing the vibration on your Sienna. You may try this on your car(you can put more or less washers on your bolts, just remember do not make the spring too tight, so the washer amount may vary on different vehicle). Please see the following pic for the washer size and position of CAT converter.
 

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Had the same problem as you , took to dealer and they also tightened spring tension that made the problem much worse and i mean so bad that you could feel it in the steering wheel. SO i also did the same as you and problem is MUCH better but still not completely gone, hoping toyota will address this with a TSB fix, if not i am sure they will loooose future toyota sales as this is most prevalent on many sienna vans.:|
 

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I drove 2 brand new '16's; no vibrations.
There must be a retrofit fix (tech bulletin) for this if they've addressed it at the production level.
 

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My 2016 LE has a similar drone. Around 1200 rpm. Not terrible, but obvious. Thinking about playing around with the exhaust system. I will keep you posted.
 

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Hi all. Just bought a used 2016 LE and it drones at 1250RPM as well. It has 24000 km. Not impressed. Interested to know if the fix from the first post is still working and if anyone else has had success with it. Toyota mechanic said reprogramming the ECM would do the trick.
 

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You need to be aware of the possibility of carbon monoxide leakage with this type of modification.

The purpose of the spring bolt is to keep a constant compression on a tapered/doughnut shaped gasket placed between two flanges. The spring bolt allows some system flexing as the engine rocks on it's motor mounts, and limits the total motion and vibration transmission to the exhaust system. But as it rocks, it wears down the gasket and the spring bolt tensioner takes up the slack and maintains compression and the seal. By placing washers / lock washers between the flanges, you've limited how much those flanges can come together as the gasket wears. Eventually that gasket will wear away an edge, and exhaust leakage will begin.

If you decide to do this, you must get under there and inspect it regularly with the engine running for signs of increased noise or puffs of air escaping.
 

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This is an interesting topic, as I posted a question about whether 2017 Sienna's share the drone problem with the Lexus 2016rx350, since they share the same engine transmission. It looks like the issue is widespread.
 

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I looked under my van this evening, and as suspected there should be NOTHING between the flanges. The spring should be 'clamping' the two sides together, yet be allowing the needed motion as the drivetrain rocks. The OP has created a pretty much solid system, and that puts a lot of stress on the joint to the transverse mounted muffler. Eventually either the cat flanges will leak, or the muffler connection will fail. I wouldn't do this. There must be better way to quell the resonance.
 

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Doing some research and found that the new gen Highlander is having the same issue. DIY fix seems to be removing the exhaust bracket at the oil pan ... another guy had the dealer replace the exhaust manifold with an updated part. Apparently they redesigned the manifold due to the complaints coming from their customers. No TSB yet of course.

Wonder if the Sienna and Highlander share an exhaust system and therefore have the same sort of issues.
 

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Apparently Toyota is having a problem with exhaust drone across many Lexus and Toyota models. Not sure if they are giving it much priority since it has been going on for several years now. Also, the new 2017 Highlander with the Lexus powertrain (8 speed transmission and 3.5 engine) has the drone at around 1700 to 1800 rpms. Be glad the Sienna's drone is at 1200 rpms because the 1700 to 1800 rpm drone in the Highlander is the sweet spot that the vehicle want to be at during highway driving. It would truely suck if the Sienna's drone problem occurred at highway speeds (around 2000 rpm). One solution that some Lexus owners had tried was to add dampers to the exhaust system. Some have reported that this solution helped but did not completely eliminate the problem.
 

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My brand new 16 XLE has vibrations too. I am sure it's not normal . The XLE has about 4200 miles.

I can feel a vibration when it accelerates from a stop. once it passes 1250 RPM or below 1250 RPM , the vibration is gone.The vibration happens for about 1 to 2 seconds only touch 1250RPM
I tried to put it in neutral and rev it slowly and I can also feel a little vibration at 1250 RPM , Even the car not moving i go easy on the gas paddle to 1250 RPM i can feel litte vibration .
I have my Sienna inspected by the Toyota Dealer No issues found they say is normal .But why have the vibrations only on 1250 RPM ??
Anyone have same issue and know how to fix .... ? thanks
 

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I have my 16 sienna XLE 1250 rpm vibration fix , take the car to the dealer ask to removed the exhaust bracket.No More vibration on 1250 rpm..But now have little vibration on 900 rpm from stop idle up ... Acceptable better than before .. Hopefully toyota fix the exhaust problems.
anyone know any exhaust bracket can fix the problem ??
 

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Is stupid idea , but work for me , no more vibration on 900 rpm with the paper in the gap without bracket .

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I see. Cardboard probably isn't the best solution.

I find it rediculous that we have to resort to such tinkering in order to make these 'premium' vans operate normally. I traded in a 2013 Dodge Grand Caravan in an attempt to avoid doing this ... truth is, my Dodge ran smoother (and more efficiently) than my 2016 LE.
 

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I just bought a certified used 2014 Sienna that vibrates at 1200 rpm. The tech from Premier Toyota in Amherst told me this was normal! I am glad to hear others have the same complaint. I think the tech didn't know how to fix the problem (or just didn't want to) but they blew me off. I may take it to a different dealer before the 12,000 mile warranty expires, but after looking at the fine print the exhaust system repair probably won't be covered anyway and I will get stuck paying a diagnostic fee plus the actual cost of the repair. Gee, I guess they missed this defect on the 160 point check!
 
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