US hobbyist uses Claude and Codex to pass emissions test with an old Jeep

An AI enthusiast in the US, Mohammed Zourali, used AI and simple wiring to get a 32-year-old 1994 Jeep Cherokee through California's emissions test. Claude handled the diagnosis, while Codex wrote the code.

The SUV failed the test several times due to high nitrogen oxide emissions at certain speeds, and blind tuning cost him nearly $100 per retest. With a $3 Arduino Nano board, his laptop could finally read the engine data.

Since the old engine computer couldn't be reflashed, Codex wrote custom code to an EEPROM chip instead. Claude collected data during test drives and even got control of fuel pressure, doing most of the diagnostic work. No mechanic or dealer tools were needed.

The project is now on GitHub as xj-scanner under the GPLv3 open-source license. All the electronics cost less than $15 in total.