barbami

Well, I downloaded the Measure blocks and reviewed the file, apparently the Tank contents is liters not Percent (can see in the file it is 19.0 l not 19.01 as I thought from looking at the screen last night.

All said it seems that the key-on 30+ secs does reset the tank volume. I added more adblue and now the measuring block reads 27.0 l which from my understanding is a full tank (good thing since there is no more space in the tank).

Dutch VanAtlanta thanks for the adaptation information, I may still try that as I don't understand why if I could only put ~12 liters into the tank the low AdBlue alarm was on.

barbami

Well, with questions about the AdBlue reserve tank being full or not, and why if the reserve tank was full I was only able to go about 3000 mi before I would get the AdBlue low warning figured I had to do something.

I figured if the reserve tank was full but not transferring fluid to the main tank either the controller or the transfer pump was bad. If there was no fluid in the reserve tank there was a problem or blockage in the tube/hose connections between the reserve and main tank. With these potential problems only 1 thing to do, pull the reserve tank and see if it was full.

Well, the reserve tank was full, so at least I confirmed you can fill the tank from the connection behind the fuel fill door.

Next was to test the transfer pump. I pulled the transfer pump and applied 12v to the terminals and the pump didn't run. The current draw was high so I am convinced the pump is frozen. Wanting to be thorough I checked the pump connector on the car to see if there was 12V at the connection. Unfortunately there was no voltage.

I confirmed the ground side was good (almost no resistance between the connector and the frame. so now the question, can someone tell me when the controller turns the transfer pump on? Is it only when the fluid level in the main tank is low (but not low enough to trip the dash warning)? Or does it run all the time?

Ordered the pump, but would hate to put everything back together only to find I need to take it all apart again to check something else.

Appreciate the help.

lentiman

barbami, did you ever figure this out? The dealer is telling me that I ran out of Adblue at 10K miles and I never received a warning that it was low. So I'm wondering if the pump, controller, or sensor is bad in my Q7. Thanks.

Also, I tried to find rough Adblue usage but couldn't find it. How much are you guys using per 5K miles? I'm at about 10K miles and the dealer says it took 4.3 gallons. So I'd estimate roughly 2 gallons per 5K miles. Thanks.

J. Patterson

I think that depends a lot on how the vehicle is driven. Heavier throttle requires more ad blue. At least that is what my service advisor told me. MY add light came on recently right at 10000 miles and I added 5 gallons of DEF.

barbami

lentiman,
I found my problem was the transfer pump. The main tank was full and the only available AdBlue was from the uppper (injection) tank. I found that I could go about 3K miles on the ~1 gal that is in the upper tank, then the warning light about low AdBlue would come on. After replacing the transfer pump I am back to adding about 4 gals (1 and 1/2 2.5 gal jugs) of AdBlue at ~10K when I do the oil change. No warning light comes on.
From all the troubleshooting I did I found that the only level sensor is in the upper (injection) tank. So Low AdBlue light comes on when level in the upper tank is low. The lower tank I believe holds 20L (or about 5 gals), the upper tank about 1 gal. If the Dealer topped off your AdBlue and only added 4.3 gals then you were not out of AdBlue (more than 5 gals in entire system). The amount the dealer added (4.3 Gals) seems consistent with what I see (~ 4 Gals) for 10K miles..
Here is a great link that does a fantastic job of describing the system (including the details on the Q7)
Adblue with DPF FAQ: pictures, cleaning, and repair | VW TDI forum, Audi, Porsche, and Chevy Cruze diesel forum

boriquais

Barbami,

DO you happen to have the part number for this transfer pump? how hard was the replacement?

barbami

Replacement was pretty easy.

1) Holding the Main tank up with a jack, unbolt the straps that hold the tank in
2) Lower the tank to gain access to the transfer pump on the Driver side rear of the tank
3) pump held in with hose clamp style clamp, loosen and free the pump from the tank, disconnect electrical connector
4) Install clamps on the suction and discharge lines (rubber hoses) to isolate them (pinching style clamps readily available at local auto parts stores)
5) Remove the suction and discharge lines from the pump, remove the pump
6) Reverse the order to install the new pump

This way you don't have to worry about making a mess while the main tank is full (which it will be if your transfer pump is bad).

Here is the info for my transfer pump.

Transfer pump for reduction agent .
This genuine part fits your 2010 Audi Q7 3.0L.
SCR SYSTEM. V436.
Stock Code 4L0131901
Manufacturer Audi

josefprem

Did you ever figure this out.....having the same issue. Thanks

J. Patterson

Following up, Have now experienced AdBlue pump failure TWICE. First on our 2011 TDI Q7 at approx 90000 miles and recently on our 2015 TDI Q7 that we bought to replace the 2011 when it was bought back. This one failed at just under 80000 miles. First one was on my dime before emissions settlement was in effect. This one covered by TDI extended warranty. Indications are an AdBlue low warning but tank only holds about 1 1/2 gal and is full. That will take you 2 or 3000 miles then you’ll get a warning again. It’s because the upper 1 1/2 gallon tank is the active tank and the lower 4 1/2 gal tank is simply a reservoir. From observation, I believe the transfer pump runs constantly when the ignition is on keeping the upper tank full and circulating back down to the lower tank via the fill pipe. This would keep AdBlue in lower tank from freezing since the upper tank gets heated. ( Just a guess on my part)
FYI a bad transfer pump does not set any diagnostic codes. Service advisor said it’s a fairly common issue and that failed pumps typically have evidence of AdBlue leakage. My guess is that they can diagnose by checking to see if it is running when ignition is on.

'10Q7TDI_Prestige'

My first thought reading the initial thread post is why didn't you just take it to the dealer for the extended warranty settlement coverage, assuming you are in the United States.
I just had issue with DEF dripping out onto the driveway when car running, so took it to dealer and they kept it about 10 days and just kept replacing parts on it. So now I have a completely new DEF everything, lol. Also got them to resolve an oil leak they initially tried to sell me on paying for, which was likewise covered by the TDI dieselgate warranty extension. I like to work on cars, but if I can get Audi to do the work and replace everything for me, and while I drive their brand new loaner car...you bet I go in an scarf up some freshly baked cookies and take a couple double cappuccino coffees to go for the road. Let those buggers fix the car and replace as much of it as possible, LOL!