Crew Chief – OBD2 diagnostics via cheap Bluetooth scanner

I have too many vehicles. Cars, motorcycles, tractors -- they pile up when you can't say no to a project. Keeping track of everything across all of them was the problem: which parts I ordered for which thing, what codes I pulled last month, when I last changed the oil on the tractor.

It started because I got tired of typing my year/make/model into RockAuto and AutoZone every time I needed a part. So I built a browser extension that auto-fills vehicle info from a saved garage. That lasted about a week before I started bolting on more features.

The diagnostic pipeline is where I've spent the most time. The mobile app pulls OBD2 codes from those $15 Bluetooth ELM327 scanners, then sends them to an LLM with vehicle specs, known TSBs, and common failure patterns for that specific make/model/year. ranked probable causes, DIY vs shop cost estimates, severity rating, and linked a ChrisFix video for the repair. I've been tweaking the prompts and context window for months. The whole point is closing the loop: check engine light comes on, pull codes from your phone, get a report telling you what's wrong, how bad it is, and how to fix it.

Other stuff:

- 50 state selling wizard - generates the correct bill of sale, title transfer docs, and disclosure forms for any US state. - 16 vehicle types with type-specific fields (PTO type for tractors, hull material for boats, engine CC for motorcycles, etc.) - Task boards per vehicle - kanban for garage projects with parts-ordered/received/installed tracking.

TypeScript throughout. The extension, web app, and mobile app share a backend.

Free tier is 1 vehicle with full features, no credit card.

Been heads-down for a while and just now coming up for air.

Happy to answer questions about the OBD2 integration, the LLM diagnostic stuff, or the 50-state document generation.