# Step 1 Research
have wiring diagrams in random loose format: pictures, scans, PDF, text.

# Step 2 Data Entry
have ECU connector pinout in google spreadsheet form, with explicit function of each pin, often with analysis of multiple vehicles with similar pinout. Good example https://docs.google.com/spreadsheets/d/1H0cZPAJFbpprgSu1Y8BiAYzXbqddvIn-Hhod4QCVQwk

# Step 3 breakout
Break board for that connector to reduce risks, also a product by itself!

# Step 4 Start of KiCAD
Pinout data entry into KiCAD

# Step 5 Adapter
Proteus or else adapter for specific vehicle, based on steps 2, 3 and 4. Because cheaper fabrication and less labor intense.

# Step 6 Plug In
Full plug in board like Hellen if demand exists.