What diagnostic tools should a new repair shop buy first?
Short answer: Start with a capable bi-directional scan tool, a good multimeter with back probes, a battery and charging system tester, and a stable power supply; add a smoke machine and a scope as the work demands.
The first priority is a scan tool with full-system coverage and bi-directional controls for the vehicles you see most. It handles codes, live data, service resets and active tests, which covers a large share of daily diagnostic work.
Next, an automotive multimeter with quality test leads and back probes lets you verify what the scan tool suggests. A battery and charging system tester catches the many problems that start with low voltage, and a stable power supply protects vehicles during long key-on procedures and programming.
After that, a smoke machine pays for itself on EVAP and vacuum leaks, and a lab scope with current probes takes your diagnosis to the next level. Add J2534, ADAS, TPMS and key programming tools when you have the training and customer demand. Buy for the work you actually do, and budget for software updates.
Tools used for this job
General guidance only. Follow the vehicle and tool manufacturer's procedures, and confirm vehicle coverage on the tool maker's list before buying.