[LoneStarS30Z]

Hey y'all, I'm at a loss trying to fix P2309 Coil 4, P0363 Ignition Failures, and P0304 Cylinder 4 Ignition Failures.

Background: 2018 Giulia Ti Q4, 72K miles. Drove to work Monday and drove flawlessly. Attempting to leave work that day, tried to autostart and walked out to the car to discover it hadn't started and had a check engine light, but the engine was still idling normally.

Deciding to try the left, right, and center steering wheel reset to see what would happen. Upon restarting, idle was extremely rough, and I pulled codes with a cheap OBD2 scanner that pointed toward cylinder misfire.

I initially suspected a bad coil pack, so I ordered a new one to swap in with no results. I then continued to play musical coil packs and spark plugs (spark plugs showed no obvious damage) between the 4 cylinders, but I always got P2309, P0363, and P0304.

Bit the bullet on a new battery since I do live in Alaska, but a new battery didn't fix the issue. Did some more research that led to a suspected stretched serpentine belt with the P0363 code; a new belt did not fix the issue either.

Bought MultiScanECU, hooked up the car, and cleared codes hoping a full reset would work. Nope. Immediately the same codes came back. Also, monitoring each Coil shows that Coil 4 reading at 0.000 ms, which seems to confirm no power to cylinder 4's coil pack. Also tried reseating the 2 connectors on the ECU, and nothing has changed.

I've got 4 new spark plugs on order, but I doubt that'll provide a fix either. So I'm completely out of ideas now other than shooting cylinder 4's wiring harness, but even if that confirms no power is being sent, where do I look to next? I've attached some screenshots from MultiScanECU.

Any ideas? Thanks!

 

[THT]

Looks like a faulty ECU.

 

[alfan]

If the coil isn't being charged, changing plugs won't help. It appears your thinking is correct. It is either the harness or the ecu; I don't see how it could be anything else. Any wire-chewing rodents nearby?

 

[LoneStarS30Z]

If the coil isn't being charged, changing plugs won't help. It appears your thinking is correct. It is either the harness or the ecu; I don't see how it could be anything else. Any wire-chewing rodents nearby?

I didn't see any traces (fur, droppings, etc) in the engine bay or my garage. Too cold this time of year for rodents to be outside and I'm the first tenant to live in my new duplex, so no history of rodents at home either. Definitely going to do a good look around again.

I tried doing a visual check of the harness, but its damn near impossible to track without a diagram. However, didn't see anything noteworthy from the ECU to the coil harness.

 

[LoneStarS30Z]

Still doing some research, but are their any implications of swapping in a used ECU as long as the part numbers match? I'm assuming at the very least a proxi align?