I have the same code...1518...But I am lacking power in the upper rpm range...above 3000. I am thinking the secondaries are stuck shut because I don't feel the surge of power like I use to around 3400 rpm. I am going to pull the uim this week and then I'll know for sure. If not I'll just shoot it!!
Just kidding
If anyone else has info on this code 1518 it would be much appreciated.