Service diagnostic found the supply air sensor was not reading accurate air temperature. My temperature probes were reading 130 degree air while the temp sensor was reading over 200 degrees. I presented repair options and the homeowner chose to have the supply air sensor replaced. I replaced the air sensor and cycled power at the thermostat. Verified gas pressures are within range for operation. I also cleaned the flame sensor at no additional cost. The return air filter was replaced with a client supplied filter as well. No other issues were found. The system is operational at this time.