Apparently when you have a big vacuum hose leak on the turbo side, it must cause rapid use of DEF.

I got my 1000 mile countdown after fixing my vacuum leak, so I put a half gallon of DEF in my passive tank as I usually do. This surprised me, as it had not been long since I had added a half gallon, but... whatever. Oddly, my countdown did not go away over the next few hundred miles of driving which made me suspect I had a problem with the transfer system from the passive to active tank.

I pulled the splash guard on the right side and confirmed I was getting no DEF out of the supply hose. I blew compressed air, I pressurized my passive tank, but nothing. So, I pulled the left side splash guards off (I loathe you, BMW - these covers should not be so time-consuming to remove/install). I pulled the hose off the tank and found I had not blockage either direction.

The only explanation is that.... I was out of DEF in the passive tank despite having added a half gallon just maybe 1000 miles ago PLUS having just added another half gallon. Sure enough, I had to add 2.5 gallons to get enough in the passive tank to overcome my sloping driveway (nose down - pickup is at the very rear of the passive tank).

So, I'd torn everything apart, blown out all the lines,.... only to ultimately discover.... I was out of DEF. Arggghhhhh!!!

AM.

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E70 2010 3.0 M57 AT Titanium Silver with Black Leather
E53 2004 3.0 M54 AT Toledo Blue with Gray Leather
E83 2008 3.0 N52 AT Silver Gray Metallic with Black Vinyl
E46 1999 2.8 M52TU 5MT Black with Tan Leather 250K+ miles (Sold, but not forgotten)