Sorry, I wasn't clear. I understand that there are multiple systems and the LED only displays codes for the engine system or something like that. In Ron's specific case, what more will a scanner say about the inoperative air injection system fault? Will it give a code more specific to the nature of the fault such as one of the scenarios presented by JimF or Steve?

Thanks,
Sixto
95 S420 ... reason this topic matters to me
87 300SDL
83 300SD ... $950, see cars forum