https://nick.detello.com/tags/obd-ii/Recent content in Obd-Ii on Nick DeTello - Nicholas DeTelloHugoen-usWed, 05 Aug 2026 00:00:00 +0000https://nick.detello.com/blog/car-grades-itself-01/Wed, 05 Aug 2026 00:00:00 +0000https://nick.detello.com/blog/car-grades-itself-01/Every car since ~1996 runs self-tests on its own emissions hardware and grades them against the manufacturer’s limits - then overwrites the results. This is about keeping them: reading OBD-II Mode 06 and watching the drift toward failure months before a fault code sets.