NHTSA Complaint #11680567 — 2019 TESLA MODEL 3

I am reaching out to report a high voltage isolation issue with my 2019 Tesla Model 3. Tesla determined the issue was caused by external factors such as grime and road salt corroding the battery seals, leading to an internal isolation fault with the high voltage battery. They deemed it out of warranty, with an estimated repair cost of $13,155.30. When I asked what preventative maintenance could have avoided this, Tesla only referred me to the owner’s manual, which simply instructs users to clean the car’s exterior. No specific maintenance regarding battery seal inspection or corrosion prevention was provided. Records from our local car wash subscription show the car has been washed regularly (at least 66 times since January 2024). The previous owner also had brake lines replaced due to corrosion under warranty, during which Tesla removed the battery in March 2023. In October 2024, the rear drive unit was replaced under warranty, yet no mention was made of battery seal corrosion during any of these service visits. At no point has Tesla’s maintenance guidance or service process addressed checking the seals for corrosion in regions where road salt is heavily used. I believe this omission creates a potential safety concern, as seal corrosion in a high voltage battery could lead to failures or hazards without prior warning. The Vermont AG Consumer Assistance Program recommended I contact your office for further assistance. This issue appears to be part of a broader pattern where Tesla attributes failures to “environmental factors” without advising owners of any specific preventative maintenance, effectively avoiding warranty responsibility while leaving potential safety issues unaddressed.