Slight update, disassembled front end. the motor for the shutters was broken and internally shorted out from my findings currently. it was stuck in open position. temp put the new shutter assembly in there and it allowed that one to open and close. put the old one in there and it would refuse to respond. this was starting from cold so that it would ensure the command to close would be sent. default is closed when car starts from cold. running the ac might bypass and have it force open regardless to get more air passed over the condenser.
anyways, the connector for the motor to the shutter assembly, it is pushed against the plastic skidplate with the assembly the shutter sits inside of under it, potentially pinching connector wires. so if the person has a bad habit of pulling forward in parking spots where the parking block is under the bumper, it does have a high chance of the connector getting damaged. mine was slightly damaged and may need to replace the harness eventually. the wires showed visually they had been pinched tight a few times.
the lin network this runs on is luckily very simple. one wire directly from the engine control module to the back of car to the negative battery sensor, than 2 other wires, one to each shutter. although there is only one shutter in the front afaik. so only 2 possibilities that the network would act up and potentially get shut down. the motor can be bought on ebay for cheap but that is what i installed inside this shutter assembly originally about 2 years ago after i reassembled the front end. the motor failed in a way that took down the network. the lin network wire that connects directly back to the engine control module is in the middle of the harness with the other 2 being power [purple] and ground [black] for the motor. applying voltage to the motor will not turn it on since there is some sort of control board inside that is expecting the signal wire to actuate and tell it what to do hence why testing from below with an oscilloscope could determine if the network signal is making it down there along with checking power and ground. if you have another motor or assembly though, quicker to simply plug new one in when car is cold start and see if it closes. when car is in off state it should open back up but unsure of the time and how long car needs to start ect for it to open back up, data i had didnt specify that much.
below is a pic of the wire harness location that allows testing and access by removing the skid plate for direct testing to the connector. this is entirely possible to diagnose confirm either network signal integrity, ground or power issue without the need of removing the front bumper saving a hour or so of work. replacing the assembly however, there might be enough room with a bit of persuasion to get the assembly out from the bottom but it would be very tight. worth a shot though.
there is a small wire harness that is about 2 feet long that splits into the shutter assembly motor and the ambient air temp sensor. this is the harness that will likely get damaged by parking blocks, it is luckily short and i also am including the part number sticker for it. the ambient air temp sensor might display wrong when messing with this harness but after a bit should reset itself to its proper temp. if a check engine displayed for it, id check the wire harness first for damage as well given the location.
if there is more clarity or something i missed please let me know and ill expand or further explain the findings since the tsb is nearly useless. also recommended to buy a oem motor given there is some sort of control board inside that can potentially fail and knock down the lin bus and potentially cause other oddities since it connects directly to the engine control module. however the chinese one i bought did last a couple years so do with that info as youd like
junction from shutter is directly to the side of the housing that holds the shutter, unsure where the other junctions are, didnt need to delve further currently. but there are not many and circuit is very easy for once lol
some symptoms are when not using ac, from cold start longer than usual oil temp warmup, decreased mpg than usual and potentially a shutter code or one of these codes that relates to lin bus or lin bus devices. do avoid replacing battery sensor at first and ensure shutter wire harness connection signal wire in the middle is intact and responds properly before throwing a new negative battery sensor or shutter assembly/motor replacement at it
attached 3 pictures and 1 wire diagram for lin bus -
