Has anyone had any luck with dropping their DEF tank and cleaning it to fix the P21B0 fault code...I used a 2 1/2 gallon bottle of DEF from AutoZone and now this code has been popping up. The last time this happened I siphoned the tank out and filled it with Motorcraft brand DEF and the code went away. Now with the Titan tank installed the DEF tank is relocated and I can't feed a hose so dropping the tank is the only option...


I own a 2011 F450 King Ranch, just in case anyone is curious...I'll post pics soon...