gk1

Does anyone with a Bentley CD know exactly what this sensor is?

My B5 S4 had no electronics connected to the motor mounts or trans mounts.

Aarononymous

It's only on the Tip quattro. If it's anything like the A8 (the only other one I've seen), There is a fluid and air chamber, it regulates the size of the air chamber at different engine speeds, to reduce vibration. Something like that.

gk1

Makes me wonder if something about them can be modified to help the idle vibration found on the tip.

Aarononymous

The A8's had a problem with a fualt so we just disconnect them and install a resistor. We're told they work normal unplugged.

gk1

I may try that to see if it makes any difference at idle.

gk1

"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."


Also it is the N144 valve per VAG-COM.
N144 Left
N145 Right


Also from Vag-Com message boards:

"There this little text from Self-study 183:

The single solenoid valves for electrohydraulical engine mounting N144, N145
are operated by the engine ECU.
They adapt the damping of the mounting in to two different operating
conditions.
In idle the valves are opened, the mountings are soft.
In driving the valves are closed, the mountings are hard.

If there is an error with signals for mountings the valves are closed.
The engine vibrates noticeably in the idle operation."<ul><li><a href="https://forums.audiworld.com/a8/msgs/35368.phtml">https://forums.audiworld.com/a8/msgs/35368.phtml</a</li></ul>

Ronhack

My 2004 S4 Avant had a problem yesterday with the fault code

"17983
Right Engine Mount
Solenoid Valve (N145),
Short to Plus"

The engine quit without warning while I was driving on the highway. I was able to coast off the highway and found somewhere to park and had the car towed home when I checked with the code reader.

What is the remedy for this? Check the wiring at the solenoid first, I suppose.
Is this very common?

Thanks,

RH

WACIV

what resistor do you use and where do I buy them? I see where you can buy a bypass for other models is there one for the D3 (2005 A8)?