A method for diagnosing a device of a vehicle, includes: generating samples of a parameter of the device; indicating whether each of the samples passed or failed based on comparisons of the samples with one of a predetermined value and a predetermined range; tracking a first number of consecutive samples compared, a second number of the first number of samples that failed, a third number of the first number of samples that failed consecutively, and a fourth number of a last predetermined number of samples compared that failed; selecting one of a normal control mode, a temporary default action mode and a permanent default action mode based on the first, second, third, and fourth numbers; and selectively setting a diagnostic trouble code (DTC) in memory when in the permanent default action mode.