I set the P1693 code last fall, as well as a compainion code which indicated low voltage/MAP sensor. I disconnected the batts. and I went away for about 1 month, then came back as just the P1693 code. Disconnecting the batts. would not clear the code/check engine light the 2nd time around. I purchased a new Map plug but, before I installed it, I lubed up the connections with dilelcetric grease( on the old MAP plug). The check engine light was out upon re-connection of the batts. A few days ago, I received another P1693 code with no companion codes displayed on the odometer. Again, it wouldn't go away with the batts. disconnected. I again greased the 3 posts within my 3 MAP plugs (OEM, TST and EZ boxes). The check engine light went out has stayed off since. Give it a try, a tube of the dilelectric grease is available at most auto/hardware stores and only a few bucks. The P1693 code is common for those that are using aftermarket fueling boxes, IMHO.
Scott W.