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17985 fault wont go away

Posted: Thu Dec 21, 2023 10:47 pm
by Frazz82
So I replaced the the engine mounts in the hope it would cure the 17985 fault code I was getting but its still there.

Does it need to be turned off using Vag-com as the inbuilt dash one I have doesn't clear it.

Re: 17985 fault wont go away

Posted: Sat Jan 20, 2024 12:25 pm
by Shoppinit
Both engine mounts?

What happens when you clear the fault? Does it reappear immediately or later?

Re: 17985 fault wont go away

Posted: Sat Jan 20, 2024 5:00 pm
by steve2003rs6
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17985 is the error code I have. Genuine Right hand engine mount is Being replaced on Friday 9th next month.
Initially it was a intermittent fault which is now a constant fault.
Clearing the fault codes with Vagcom. This fault doesn’t clear even with Vagcom as it’s a actual fault.

Re: 17985 fault wont go away

Posted: Sat Jan 20, 2024 5:17 pm
by Frazz82
Shoppinit wrote:
Sat Jan 20, 2024 12:25 pm
Both engine mounts?

What happens when you clear the fault? Does it reappear immediately or later?
Immediately soon as the engine is running so I assuming its a wiring issue.

Re: 17985 fault wont go away

Posted: Sat Jan 20, 2024 6:22 pm
by Shoppinit
Could be.

There are only 2 contacts going to the mount and they are to power the solenoid which stiffens (or relaxes, can't remember which) the mount. I'm guessing that the ECU checks the resistance of the solenoid coil to make sure it hasn't burned out. If there is no resistance, or too much, then it throws a fault.

You could try putting a resistor across instead of plugging it into the mount to see if the fault goes away. If it does then it's the engine mount, if not, then it's likely the wiring upstream.

I have seen values of 19 Ohms mentioned online for the resistance, when people replace the active mounts with passive ones, to fool the ECU. You could always measure the resistance of the other mount using a multimeter to check. If you put 12V through a 19 Ohm resistor then you are likely going to need to dissipate around 8W so you can't use regular 0.25W signal resistors... at least, not for very long :) Something like this would probably work:

https://www.amazon.co.uk/Sourcingmap-Al ... C65&sr=8-6

Or just make a temporary loom to connect the right mount to the left mount connector to see what happens with the codes.

Re: 17985 fault wont go away

Posted: Thu Jan 25, 2024 9:01 am
by Frazz82
Little update on this. Found the reason faults still there.............lad never replaced the mount and just did the NS one. He told my mate who owns the garage it had been done but turns out never did it as he said the engine would need to come out so just binned it off. I know this isnt the case so what I am after is a how to guide for OS and I am just going to do it myself

Re: 17985 fault wont go away

Posted: Thu Jan 25, 2024 9:32 am
by Lander91
Frazz82 wrote:
Thu Jan 25, 2024 9:01 am
Little update on this. Found the reason faults still there.............lad never replaced the mount and just did the NS one. He told my mate who owns the garage it had been done but turns out never did it as he said the engine would need to come out so just binned it off. I know this isnt the case so what I am after is a how to guide for OS and I am just going to do it myself
Wow.... :shock: at least he's honest....

Re: 17985 fault wont go away

Posted: Thu Jan 25, 2024 2:07 pm
by Felix2566
Hope they will refund you the value of the mount not fitted?

Re: 17985 fault wont go away

Posted: Thu Jan 25, 2024 7:17 pm
by Frazz82
Its going back in to get sorted so all good.

Problem my mate has is all the areas Mechanics and other trades are going to BAE Systems an local business's cant compete with what the yard offer.

Re: 17985 fault wont go away

Posted: Fri Feb 09, 2024 9:44 am
by steve2003rs6
My car in today for right hand engine mount fault 17985. Original Audi part being fitted.
Also having the brake fluid change whilst it’s in the garage.
In addition fault on front parking assist being done.

Hopefully all sorted today.

Re: 17985 fault wont go away

Posted: Fri Feb 09, 2024 8:22 pm
by steve2003rs6
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Just picked up the car after 5 hours work.
Right hand genuine Audi hydraulic engine mount installed and 17985 error code has been erased. Work was done with Engine in situ. Had to bastardise a spanner to suit.

2 year Brake fluid change performed. ATE 200 Dot 4.

Park assist error. All sensors tested ok.
Parking sensor module replaced and front parking buzzer also replaced.
Ran diagnostic. Error code has been removed.
All in all very satisfied.

Re: 17985 fault wont go away

Posted: Fri Feb 09, 2024 8:25 pm
by Shoppinit
Yay. Happy days when the list of fault codes is empty. Never lasts for long though :)

Re: 17985 fault wont go away

Posted: Fri Feb 09, 2024 8:34 pm
by steve2003rs6
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Really shopp ????!!!!!!!
I thought these cars were really well made.

Thought I would celebrate. (Cheers Ben)
Not that I need any excuses.

Re: 17985 fault wont go away

Posted: Fri Feb 09, 2024 8:46 pm
by steve2003rs6
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Still have the auto central locking to sort out.
I have changed the door locks three times. Still the errors persist.
Going to change the comfort control module next to see if that sorts it. The one under the passengers carpet.
I have bought a module so just need to have it installed.

Re: 17985 fault wont go away

Posted: Thu Feb 15, 2024 6:41 pm
by Frazz82
Glad it's sorted Steve. I am.sure mine would have been had the bothered to change it 😕. It's going back in soon justing on the new air con condenser and dryer to arrive.