NHTSA Complaint #11582901 — 2018 TESLA MODEL 3

I have a 2018 Tesla Mode 3. It is one of the early Model 3 on roads. I have had around 10 issues in the car over the past 6 years of ownership; and most of them were fixed during warranty. My car has no accidents, no water damages (only hand washed), single driver driven and well maintained. Around a month ago, I got an alert in the car “Condition Detected with Controller”. Tesla Service did remote check and stated that VCFRONT (Front Body Controller) needs to be replaced for $900. I took the car for this fix and then heard that VCFRONT Controller is fine, but I need a replacement of Harness and Steering Rack for $4200, as they see corrosion. I told them that I have no issues with driving or anything else, as $4200 is around 25% of the value of the car. I was advised, pay for this amount or take the car. I got my car without fix. My concern include (i) if this is corrosion issue (Model S 2018 and before also had the same issue and there was a recall), then is it their part quality or design quality issue or is it a normal car’s aging issue? (ii) I see malpractice of charging exorbitant $4200 for something I do not see any issues in driving or anything else, and importantly, not sure how are my future repairs going to look like $$ wise. I have request for NHSTA – can I show my car to any entity like yours (and not Tesla Service) to get an advise whether (a) this is a corrosion issue by manufacturer or normal car’s aging issue (b) is it critical car to replace one or both parts (c) is this a malpractice to burden owners with this high cost of maintenance, once it is out of warranty? (Please note that Tesla never offered extended warranty for my car)