This is the biggest practical downside. Toyota changes part numbers constantly. A free 2015 EPC will not know that part number 04465-06100 (a brake pad set) was discontinued in 2019 and superseded by 04465-06101 . You will order the old number, the dealer will say "discontinued," and you will have wasted a week.
Toyota Electronic Parts Catalog (EPC) is a professional software tool used by dealerships to identify genuine OEM parts for Toyota, Lexus, and Scion vehicles. While "free download" links are common online, they are typically unofficial and carry significant security risks. 1. Official and Legitimate Access Toyota Electronic Parts Catalog -EPC- free download
Let’s cut to the chase. Toyota is a multinational corporation that aggressively protects its intellectual property. This is the biggest practical downside
The official Toyota EPC is not cheap. A subscription to the official TIS (Technical Information System) costs hundreds of dollars annually. For a professional shop, that is a write-off. For a teenager fixing a 1998 Supra or a father restoring a 1985 Land Cruiser, $500+ per year is not feasible. You will order the old number, the dealer