car broke down 2km after safety cert

[V8 FAIRMONT]

Hey guys, i bought a car from way up north and drove it down 850km legally with no problems. drove it up to the mechanic the other day to get a safety and drove fine, but when i got there the water was empty. played around and fixed the leaky hose, found an oil leak...coming from a very old filter, changed that and all ended up being good, i got my safety and went on my way. 2km up the road my car just died on a hill and lost all power, engine wouldnt crank and definantly wasnt flat battery or low fuel (i thought it was fuel) called my mate to come help and he found the car was getting no spark and had no idea why, till i told him about this mongoose module i saw under the dash.

somehow the immobilizer kicked in while i was driving (never had any issues with it before, didnt even know it was still working!!) so i had to get it towed 5 mins down the road and now wait even longer to get it registered. i wanted to drive it so bad. unluckyyyy