I'm experiencing a strange situation with my 2016 Fiat 500X Trekking AWD with 2.4L/9-Speed, and I'm hoping someone else has maybe had a similar issue and figured out how to resolve it. During 100+ degree F weather a few weeks ago, the engine cooling fan motor overheated, seized, and blew the 50A fuse in the engine compartment fuse/distribution unit while I was stuck in stop-and-go traffic, which also caused a high temp warning message and check engine light. After letting the car cool off and traffic clear up, I was able to drive 200+ miles back home without any issues.
I was aware of Customer Satisfaction Notice V54 that Fiat issued regarding the engine cooling fan, and I checked my fan which seemed okay, so I didn't worry about it, especially since my warranty has already expired, I figured I would just replace it myself if/when it failed. So, I ordered a replacement fan assembly, installed it, replaced the blown fuse, and tried to start the engine, but the battery was discharged. The car sat for a little over a week waiting for parts to arrive, so I didn't think much of it, and just recharged the battery overnight and the next day the car started right up and ran great. The warning message and check engine light self-cleared, and the only stored code was P0481 - Cooling Fan 2 Control Circuit Malfunction, which I cleared. At that point, everything seemed back to normal.
Two days later the engine wouldn't start, as the battery was discharged again. I check the battery voltage, and it was ~10.8V which is expected if one of the six cells inside the battery was bad. Given that the battery was 5+ years old, it made sense, although the timing of it happening right after the fan failure seemed odd. I purchased a new battery, put it on my charger for a few hours, installed it, and then checked for possible current draw while the car was off, and was surprised to see ~1.5A between the disconnected negative battery cable and negative battery terminal through my Fluke meter. 1.5A is a lot of current draw for a car that's completely turned off.
So, I started tracking down the source of the current draw, beginning at the engine compartment fuses/distribution unit adjacent to the battery. Removing both F1 (70A fuse) and F2 (60A fuse) stopped the current draw, these two fuses feed the Module Body Computer under the left side of the dash. The Module Body Computer also has two rows of fuses, I removed all of them and checked for current draw expecting to see none, but there is still 0.5A current draw. Installing F36 adds 0.8A of additional current draw, and installing F53 adds 0.2A of additional current draw. So, the 1.5A of current draw at the battery seems to be a combination of three sources, those being the Module Body Computer, one or more devices powered by F36, and one or more devices powered by F53.
The really strange thing is that when the engine is running, everything works normally, I can't find anything that doesn't, and there's no messages in the display, no check engine light, and no stored codes when I check with my scanner. But once I turn the car off, the 1.5A current draw is still there, so for now I'm disconnecting the negative battery cable (easy to do with the flip lever) each time I turn the car off to prevent the battery from discharging.
I've read that some vehicles have had the Module Body Computer flashed with updated programming to solve issues such as lights or locks not working correctly, but I haven't ready about any other car-off current draw situations like mine. I've also read that the Module Body Computer is programmed to the VIN and can only be used in that car thereafter, meaning that if it can't be fixed with a flashed update, it needs to be replaced with a new one that will need to be setup by the dealer. I'm concerned that my Module Body Computer may have an internal problem that for whatever reason doesn't prevent it from functioning correctly when the car is on, but allows current draw when the car is off, or at least that's the behavior that I'm seeing following the engine cooling fan failure.
Please let me know if anyone has any experience or information that might be helpful, I haven't contacted the dealer yet, as there aren't any Fiat Studios in my area, only other dealers that happen to sell a few new Fiats, and even they are not close by, so I'm trying to figure out as much as I can before I reach in that direction for help. Thanks!