A diagnostic system for an internal combustion engine includes an intake air temperature (IAT) determination module, a reference temperature determination module, and an adaptive learning module. The IAT determination modules determines a first IAT using an IAT sensor at a first time and determines a second IAT using the IAT sensor at a second time. The reference temperature determination module determines a first frequency based on a first voltage output of a MAF sensor at the first time and determines a second frequency based on a second voltage output of the MAF sensor at the second time. The adaptive learning module determines a temperature-frequency relationship based on the first IAT, the second IAT, the first frequency and the second frequency.