The L.A. "pothole" Arnold Schwarzenegger fixed was indeed a service trench for the gas company ... but TMZ has learned that service was done months ago, and that's why Arnold went all DIY on the ditch.
We got to the bottom of Arnold's roadwork adventure -- a story with more twists and turns than one of his action blockbusters.
MAN WITH A PLAN
ICYMI, Arnold rolled up his sleeves and went to work Tuesday ... using muscle, Quikrete and some tools to pave over what he saw as a "giant pothole.