So, I was driving in town about a week ago, coming to a red light in a line of traffic. As I was coming to a stop, I noticed the engine light came on for a few seconds, then went off, then the oil pressure light came on for a few seconds and then went off like the check engine light. I came to a stop without realizing the engine had died (the music was up). I tried to crank it over and it did eventually start with much effort (and a little grinding which could have occurred from over cranking). At this point people behind me were not too happy as it was nearing rush hour traffic. I got it moving but while shifting it was trying to die again. I managed to get it pulled off to a somewhat safer place before it died and would not crank at all.

Got it towed home and with my small amount of mechanical skill (and google/youtube) attempted to diagnose it. I checked the engine grounds, there is two of them, one small wire heading off the negative battery terminal to the body and a larger one heading to the engine. They're not in the best shape but they don't appear to be broken and still conduct when a dmm probe is connected to them (I get less voltage on them as opposed to direct battery terminals, around 4 volts less). I checked the terminals coming off the starter and same idea, I get a few volts less. After dark, I turn on the headlights and try to turn the key to see if the lights dim at all, but they don't. If I leave the key in the ignition in the on position without trying to crank it, after 30 seconds or so the engine light comes on so I connect my obd2 scanner to it but it fails to make any connection to the ecm at all (personally think it's the ecm).

Talked to one person who said they had a similar issue with similar symptoms and it turned out to be a crankshaft sensor. Personally I believe it to be an ecm or sensor issue myself as the engine died while in motion without any loss of power. Currently have the battery on a charger as I've been trying to diagnose it and have drained some power (which could also explain the volts dropping on the grounds/starter).

Anyone with similar issues or any help at all would be grateful. I've only owned the car for 2 months and so far it's been nothing but a headache (I have no idea what repairs or maintenance has been done to it other than what I've done, which is change the rad, and replace a blinker light bulb so far). It has around 190k km (or 120k m) on it. It's pretty much all stock except the stereo.

 

Changed batt terminals and ran new grounds, volts are up to a better reading but still no crank, still can't connect to ecu/ecm. Fuses and relays are all fine.