P1577 - Right Side Engine Mount Solenoid Valve. I'm confused!

[Cyrik]

Played code roulette with my car this morning. Scanned and got a code for the right side engine mount - OPEN CIRCUIT. There's a couple things that confuse me on this:

1. Open circuit simply means it's either not connected or shorted, correct?

2. IIRC, I thought only the left side (driver-side) engine mount actually has a sensor going to it? How can the car tell there's something wrong with the right side engine mount when there's no sensors that connect to it? Am I missing something? I don't remember anything going to the right side engine mount... so this has me lost. Any ideas?

I know what the code actually means, looking to replace mounts here soon since they're originals (I'm at 120k) but still quite confused how I got this. Thoughts?

[rhfosu]

I've never had a car with active mounts, but my guess is the left side mount can detect excess movement caused by a failing mount on the other side, and somehow knows the difference.

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[vce1232000]

https://www.europaparts.com/motor-mo...0199379bj.html
they are vinn# specific. Some do have it on the right side

[Cyrik]

I've never had a car with active mounts, but my guess is the left side mount can detect excess movement caused by a failing mount on the other side, and somehow knows the difference.

That definitely would make sense, those damn germans 😂

https://www.europaparts.com/motor-mo...0199379bj.html
they are vinn# specific. Some do have it on the right side

Had no idea some were VIN specific, thanks for the info, maybe my memory is just hazy and I don't remember if there was a connector on mine, I'll have to double check again sometime.

As far as motor mounts go, anyone here recommend the 034 mounts? Heard they can cause more vibration but are much more solid.

[rhfosu]

That definitely would make sense, those damn germans 😂



Had no idea some were VIN specific, thanks for the info, maybe my memory is just hazy and I don't remember if there was a connector on mine, I'll have to double check again sometime.

As far as motor mounts go, anyone here recommend the 034 mounts? Heard they can cause more vibration but are much more solid.

I had the street density on my sedan. I liked them a lot. I didn't notice any extra NVH. When my mounts go on my wagon, I'll buy them again.

[vce1232000]

That definitely would make sense, those damn germans 😂



Had no idea some were VIN specific, thanks for the info, maybe my memory is just hazy and I don't remember if there was a connector on mine, I'll have to double check again sometime.

As far as motor mounts go, anyone here recommend the 034 mounts? Heard they can cause more vibration but are much more solid.

I have 034 mts . I have not noticed any vibration from stock. I a resistor on the plug to avoid soft code error on vcds

[Cyrik]

Thanks for the really quick info guys! You guys are awesome!!!

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[Theiceman]

I've never had a car with active mounts, but my guess is the left side mount can detect excess movement caused by a failing mount on the other side, and somehow knows the difference.

Sent from my moto z4 using Audizine mobile app

im not sure but i dont think so ... there is no real feedback mechanism. i think there is just one wire going in and it activates a solenoid i think , thats it.. i would think it is reacting to mapping only with no adaptability or feedback.

Never know though, those krauts are pretty crafty.

[rhfosu]

im not sure but i dont think so ... there is no real feedback mechanism. i think there is just one wire going in and it activates a solenoid i think , thats it.. i would think it is reacting to mapping only with no adaptability or feedback.

Never know though, those krauts are pretty crafty.

Probably. Personally, I think this code only makes sense if both mounts are active. Like you said. But if they could save $1 by making one side active, they would lol.

[wding2000]

im not sure but i dont think so ... there is no real feedback mechanism. i think there is just one wire going in and it activates a solenoid i think , thats it.. i would think it is reacting to mapping only with no adaptability or feedback.

Never know though, those krauts are pretty crafty.

I think it can change to firm or comfortable by electric signal. That is why they are hydraulic and can fail and leak. And if it is on your left, it will also on right side - either both or none.

[wding2000]

I am currently on the 2nd on left, and 3rd on the right. Right side is prone to failure being closer to turbo and exhaust.

[Theiceman]

i have neither... odd how some cars have it.

[wding2000]

My guess: some car has Sport / Normal modes, which change motor mount stiffness.

[rhfosu]

I think it can change to firm or comfortable by electric signal. That is why they are hydraulic and can fail and leak. And if it is on your left, it will also on right side - either both or none.

Not sure that is true. I think there are some cars that only have it on the driver side. Car in this DIY vid only had it on the D side.

https://www.youtube.com/watch?v=1lRFRiA-W2w

[rhfosu]

i have neither... odd how some cars have it.

Seems like they came on cars with auto trans only? Just looking at the vin split vce posted. That would make sense, since MT cars didn't have a sport mode.

I've owned 2 MT B7s, 07 and 08. Neither had active mounts.

Cyrik, you have a tip? Let us know if you have both mounts.

[Theiceman]

could it have anything to do with the harmonics or torque in an auto ? just wondering. Why would a sport mode car only have it on one side ?

makes sense that in " sport mode" it would stiffen, but why engine mounts and why only one side ... ??

hmmmm.. this is a good one

[rhfosu]

could it have anything to do with the harmonics or torque in an auto ? just wondering. Why would a sport mode car only have it on one side ?

makes sense that in " sport mode" it would stiffen, but why engine mounts and why only one side ... ??

hmmmm.. this is a good one

Yeah, I can't find much on the subject. I guess nobody was all too interested in laying down the specifics on A4 engine mounts until now.

[rhfosu]

Question came up here on a Phil thread, but was not answered. He had only the driver side active mount.

https://www.audizine.com/forum/showt...s-Got-to-do-it

[rhfosu]

Does appear they are tip only, but the purpose was not for "sport" mode. Seems like they dampen torque converter vibes.

https://www.audizine.com/forum/showt...tor-soft-codes

"the way the mounts work is that there is a fluid chamber with a plastic body in the middle of it, with small channel cut through it. this allows fluid from the top chamber, through the plastic body, to the bottom chamber. the bottom chamber is rubber lined and can deform under pressure. there is also an airway vented to atmosphere, with a rubber membrane separating the fluid from the atmosphere. a solenoid valve, controlled by the motronic, can open or close the airway.

below 1100 rpm (i.e idle), the engine vibrations are not enough to force fluid from the top chamber, through the passageway to the bottom chamber. the airway is open (solenoid valve open). the rubber membrane creates a soft cushion which absorbs the high frequency vibrations.

above 1100 rpm the soleniod valve is closed which blocks the airway and so "hardens" the mount (the fluid has nowhere to go). thus the mount is effectively solid.

the high frequency vibrations at speed are absorbed by the membrane (as in the idle case), while the more damaging low frequency vibrations cause the fluid to force itself through the chamber in the plastic body to the lower chamber, forcing the (lower) rubber chamber to distort - effectively absorbing the vibrations."

[Theiceman]

Look at that. My wild ass guesses were right.
Activates a solenoid based on a map to counteract harmonics for a tip.
I'm buying a lottery ticket tonight


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[rhfosu]

Looks like it. And at some point they decided one was enough.

Look at that. My wild ass guesses were right.
Activates a solenoid based on a map to counteract harmonics for a tip.
I'm buying a lottery ticket tonight


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Sent from my moto z4 using Audizine mobile app

[Cyrik]

Seems like they came on cars with auto trans only? Just looking at the vin split vce posted. That would make sense, since MT cars didn't have a sport mode.

I've owned 2 MT B7s, 07 and 08. Neither had active mounts.

Cyrik, you have a tip? Let us know if you have both mounts.

Yup, 07 Tip. Like I said in my first post IIRC I only have 1 sensor on the driver-side. Don't remember there being a connector on the passenger mount.

[rhfosu]

Well, if that's true, then there's still one mystery remaining.

Yup, 07 Tip. Like I said in my first post IIRC I only have 1 sensor on the driver-side. Don't remember there being a connector on the passenger mount.

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[Cyrik]

Activates a solenoid based on a map to counteract harmonics for a tip.

Would a tune have anything to do with this? Tuned for 3 weeks now and I got this code after. Think there's any correlation?

[rhfosu]

Would a tune have anything to do with this? Tuned for 3 weeks now and I got this code after. Think there's any correlation?

Very doubtful. Unless the extra POWAH of the additional boost finished off your mount.

It's more just curious that Audi would confuse right and left.

[wding2000]

From ECS
https://www.ecstuning.com/b-genuine-...h/8e0199379bj/

Hydraulic / Electric Engine Mount - Priced Each
Eliminate excessive engine vibrations
For automatic transmission vehicles. Fits left side only up to VIN 8E-7-149290, split is in the 2007 model year. Fits left and right side after VIN split

Tip, one up to 2007, two afterwards.

[Cyrik]

Very doubtful. Unless the extra POWAH of the additional boost finished off your mount.

It's more just curious that Audi would confuse right and left.

Hahaha the extra boost is probably what it was. Time to replace em anyway. Weird what Audi has done with motor mounts on different tranny and model year setups.

[vce1232000]

Would a tune have anything to do with this? Tuned for 3 weeks now and I got this code after. Think there's any correlation?

Very doubtful. Unless the extra POWAH of the additional boost finished off your mount.

coincidence . My oem mts was still when I change them 2 years after I my KO4

[Theiceman]

On mine the aluminum housing around them crumbled.

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[Jayz691]

To answer some questions, since I just replaced mine. Earlier tip cars with active mounts only have it on one side. Later cars, after vin split, have them on both sides, like mine. They are active mounts, which get softer at idle, and stiffen up(valve closes) on acceleration and driving. If there is a fault, it will stay stiff(default), which will cause added vibration on idle in gear. I changed mine with Hudson from eeuroparts.com, $96/ea. Got much better. One was bad and leaking.Attachment 184414Attachment 1844150612201720.jpeg

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[Wreckammended]

How difficult are the mounts to change?

[Cyrik]

How difficult are the mounts to change?

Nice necro bump lol. Forgot I made this post years ago.

Not difficult as long as you have a way to lift/support the engine to make enough room to get the mounts out. I did this on a lift and lifted the engine with a pole jack straight on the oil pan (make sure you use a buffer of some kind like a piece of wood to spread the weight over a larger surface or you WILL damage/dent your oil pan!)

I recommend doing a subframe alignment while you're at it too since you'll be messing with the subframe to make enough room to get the mounts out. If I remember correctly you might need to replace your subframe bolts as they are Torque-To-Yeild (one time use) or you have the possibility of hearing a creaking noise when driving around corners.

Engine Mount guide: https://www.youtube.com/watch?v=O0OQEzcobMI

Subframe alignment guide (you are changing geometry of the front end so get a wheel alignment afterwards as well!): https://www.audizine.com/forum/showt...rame-Alignment!