I have a 06 Chevy cobalt no codes just monitors won't set for evap and cat but did all repairs and did drive cycles like 3000 miles worth and monitors won't set also needs to pass for ny inspection

Hi, this is Bo, an auto expert on RepairPal's Car Genius team! If your 2006 Cobalt has no codes but the EVAP and catalyst monitors still won’t set after 3,000 miles, that’s like running a marathon and never crossing the finish line—frustrating and suspicious. First, make sure your fuel tank is between 1/4 and 3/4 full. The EVAP monitor won’t run if the tank is too full or too empty. Also, check that your battery hasn’t been disconnected recently—any loss of power resets the monitors. The catalyst monitor is picky about conditions. It needs a cold start, smooth idle, and steady cruising at highway speeds. If your thermostat is stuck open or your O2 sensors are lazy (but not bad enough to throw a code), the monitor may never complete. You might also have a software glitch in the PCM. Some GM vehicles from this era had updates available to fix monitor readiness issues. A dealer or shop with GM scan tools can check for that. If you need any further advice or want help finding a trusted RepairPal shop in your area, please feel free to call us at 877-913-1554.