It passed the safety inspection with no problems, but the mechanics are stumped on why only 3 of the 5 tests are "showing up" for the Missouri emission test. Two of the tests consistenly won't even register so they don't know what to suggest to fix it. Other than driving it more.......any ideas.
Won't pass Mo emissions test, mechanics are stumped on 2004 Hyundai Sonata
Are you referring to 'readiness codes'?? Bring to Hyundai to verify proper function of OBDII system.
have competent technician check it