I work with OEM EFI cars as well. Personally rely on data list more than codes (as many issues won't/take forever to set a code for anyway).

Don't find it necessary for aftermarket efi to have this but guess it could make some diagnostics easier.

69 Charger. 438ci Gen2 hemi. Flex fuel. Holley HP efi. 650rwhp @7250 510rwtq @5700