Our take

Reads and clears generic OBD2 codes on anything built after 1996 and tests 12V cranking voltage, which between them cover the two failures that actually strand people. It will not touch ABS, airbag or transmission codes, because those are manufacturer-specific and need a bidirectional tool at roughly three times the price. Buy it to find out whether a check-engine light is a loose fuel cap before a shop charges you to say so. Wrong pick for a European car, where the live-data refresh over CAN is slow enough that watching fuel trims in real time is more irritating than informative.

Best for: Owners of post-1996 Japanese or American cars who want to triage a warning light