2009 Pilot Vibration/Sound

Customer/friend complaint - vibration at 20mph and 40mph during Accel, decel, and cruising.

Sounds like it is coming from the rear. I crawled under it and didn't see anything obvious. Didn't feel any play on u joints. No torn axle boots or bushings anywhere.

I put the vehicle in the air and had him "drive" it with traction control off and was able to replicate the issue. I couldn't see anything odd happening underneath it but could hear it.

Wheel bearings are ok.

He said that he had some used tires installed last weekend and that's when he noticed it. He said they balanced them.

The rubber around the carrier bearing in the driveshaft is in good shape.

He has sent me a bunch of links to forums of people having issues from the Honda cylinder deactivation set up. Nothing says exactly what the problem with the system is, just that it can lead to worn engine mounts, vibrations, spark plug fouling, and oil consumption.

He has a basic code reader and nothing came up with it.

Any thoughts or info on the vcd topic? I couldn't find any tsbs on it and haven't heard of them causing any problems before now. I would think you'd be able to watch a PID to see if it was activating in relation to the issue but not sure why it would be doing that during acceleration without a code and at set speeds.

What else can he look for?

Thanks!

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I'll add that he found a place that sells basically a resister that you install in line with the ect to trick the computer into thinking the temp is cooler than it actually is by a few degrees in order to not activate the vcd system.

I'm thinking that if the problem is happening when it's cold, it can't be the vcd system because it wouldn't be active until the engine is at operating temp.

I'm not super familiar with the system. The

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If the vibration was a cylinder shutdown issue like you I think it would be load related rather than speed related ie applying throttle would bring all the cylinders back on line. While if I had a Honda I with the system I would almost certainly trick it into not working but I don't think it is the cause in this case As it seems to be vehicle speed rather than RPM related it brings the focus back on to the tyres , certainly the speed range is about right for a wheel balance issue.

"eco" light activated during the event?

Thanks for the replies guys. I really don't think it's an engine related issue. I'm leaning toward rear end of some sort. He wants me to do a diff service today. I'll get another look at it then.

He brought it to a shop and they told him the diff is destroyed and the axles were ripped right out of it which sounds like nonsense.

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Alright, I have a lot more info now but still not sure what it is.

The fluid change did nothing and I am ruling out the rear end. I initially thought it was the center support bearing but that looks ok.

With it in the air and "driving" I didn't see anything abnormal there or the rear end. The noise that I thought was coming from the back is some exhaust reverb through my scissor lift, I believe.

Found a code for the vrm-4 unit, 77-1, powertrain system failure. Cleared that, drove it, cycled the key a few times and it didn't come back. Mitchel basically says to check rear end fluid and replace control unit if you get that code and that it means the diff experienced a high temp.

The data in the photo looks odd, with target vs actual while accelerating. I'm not sure what to think of that. There was a test in my scantool that checks the right and rear electro magnetic coils and both sides passed.

I found a loose right side inner tie rod but don't think it is related to this. It also doesn't feel like a tire vibration.

I also found that I could active the active motor mounts and that caused some vibration with the KOEO. Not sure if that is normal. It does have 200k+ miles in it.

Drivetrain really isn't my strong point but maybe it will be after this!

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I am still thinking a tyre issue. With regard to the slight play in the tie bar I agrre I found in my experience play amplifies tyre, brake and drivetrain vibrations but is never the root cause.

That's a good point Andy. I didn't think of that. Thanks.

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He said that he had some used tires installed last weekend and that's when he noticed it. He said they balanced them.

I think this is the place to focus. I've found that tires can pick out specific load or speed ranges to act up, but be fine otherwise. What kind of shape are the front tires in? I'd suggest rotating the tires front to back, see if the symptom moves/changes.

Like you saw, the 77-1 code can safely be ignored as long as it doesn't return. The VCM system and the active mounts will usually only show up as a problem on acceleration or light cruise. If the problem is happening cold, then it's also less likely to be something like a TCC shudder.

The tire rotation did the change anything. Still a vibration at about 20mph and 45mph.

It happens regardless of throttle input at those speeds. Decel, cruise, coast, accel.

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Tutti57 wrote: The tire rotation did the change anything. Still a vibration at about 20mph and 45mph.

Damn, sorry sir, thought it was worth a try. :silly:

I've seen Honda front CV axles cause vibrations at that speed range, but it's almost always on acceleration only. Never seen a failed rear axle. If it's AWD you can try taking the rear driveshaft out for testing purposes, but I still don't think a drivetrain problem matches your symptoms.

I fixed the inner tie rod and he ended up getting new tires put on. He needed to do all of that work anyway.

The problem ended up being a binding u-joint. I didn't end up solving this one but he's a friend of mine so I'm glad it's getting worked out and I did learn a little on it.

Thanks for reading and the replies!

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