This refines the major error code into a specific fault instance for the last non-fatal error on this card. Two errors sharing the same major code but different minor codes usually indicate the same class of problem occurring in different sub-components, such as different memory banks, which matters when deciding if a pattern of failures points to one bad chip versus a systemic design issue. For example, cardDiagNonFatalErrMinor equal to 3 alongside major code 14 might pinpoint bank 3 of onboard SRAM as the specific failing memory device.