2012 TDI. My metering module started dumping DEF at alarming rate. Warranty repair was still 'waiting for parts' after months, and dealer could/did not want to provide a similar car to tow my camper. So picked up the car and tuned out the system. Have been driving for over a year now.
But still have all the 'DEF' hardware installed (even tank with fluid in it).

Next time under the car, I want to take off equipment (and drain the tanks) that is easy to reach.
Any tips, suggestions, links?

There may or may not be a 'delete' tune in the future (initially planned to do, but now less convinced since car is doing everything fine, so not really missing the additional (how much?) torque and power. And not sure if/how much gas mileage with improve.

 

The only thing that really needs to be deleted in terms of physical hardware is the catalytic converter (for the NOx system only). Removal is pretty easy, as it is just a few bolts on either end and it slips right out. Probably the most annoying part is removing it from the exhaust hanger, but that isn't too terrible if you employ the help of some spray silicon lubricant and work it between the rubber and the metal rod. There are.... three? (trying to remember now) items that need to be pulled from the exhaust: The DEF injector, the post-cat sensor, and, I think, a pre-cat sensor.

I did not remove the tanks or these items from my vehicle when I disabled the reductant system. I put each inside a ziploc bag, rolled it up, and zip-tied it to the undercarriage. This way, if a restoration of the system is needed at some point in the future, it is hopefully easier for whomever does that. For the tanks, I am not sure why, but about a week after the removal, all the DEF decided to just pump itself onto the ground through the injector, so the tanks basically took care of themselves in that regard. Both are empty now and I did not drain either one. Again, I left them in the vehicle just to prevent any need to store them, so the only part of that system that I have hiding in my garage is the catalytic converter. It would certainly free up some undercarriage space to remove tanks, and probably a little weight, but I doubt either would be a noticeable savings unless you wanted to install an air tank or something similar in their place.

 

So, my understanding is you pulled the car from dealership and then 'tuned out'/disabled the SCR system via unmentioned tuning platform.

You've got the Gen 1 TDI 3.0 w/8spd tranny in your 2012, so yeah, if you haven't yet tuned the motor, then you definitely should. Malone/Tunezilla's Gen 1 TDI Stage 1 provides = +43 HP (268 @ crank), and +65 LB-FT (470 LB-FT @ crank), and is best if you are towing and still have ANY emissions gear active on the car, and it is a very noticeable increase in HP and torque output #s. You'll feel it, and it supports increased fuel economy as a bonus. I'm referencing to my Malone/Tunezilla tune on my '10 TDI, which is the same engine, but w/ 6spd tranny, so my Q7 is just basically heavier and gets a few less mpg than your '12 Q7 TDI.

If you did it via the Tunezilla/Malone platform, then you'll most likely be qualified for a tuning discount when you go back into their online tuning portal, so best bet on Tunezilla is wait for a sale around a jajor holiday if you want to save off retail pricing, and then buy the Stage 2 (an extra $50), as that way you get the Stage 1 included and can play around with all of their tune options via their online tuning portal...super easy and quick. I've been playing around this Summer with the Stage 2 tune on mine, and am switching it back to the Stage 1 again for max fuel economy (road trips) and towing use.

One of the most notable considerations on your '12 is that Malone/Tunezilla also offer a TCU 'roll-back' to the original factory TCU tune for the 8spd Aisin transmission. If unaware of that, then be sure you read up on their tuning site tabs (ECU/TCU/etc.) before you do anything else. Let me stress that when you've already purchased any tuning from Tunezilla, then you get an 'offset' credit for what you've already bought when selecting additional tuning options or 'retunes' via their online tuning platform, so there's a ton of value built into the Tunezilla tuning platform.

I'd suggest you go read ALL about it.