engine line on but no fault code

If the malfunction indicator light is on, there are codes and data stored which could be accessed by a technician with a scanner. I don't know how the light could be on with no codes and data. I'd recommend a Nissan specialist. Here's a directory link for you: https://repairpal.com/nissan-repair-in-brookeville-maryland

think they are missing something, light on means there is a code, try disconnecting the battery for 10-15 seconds and then reconnect, this will clear the memory, if the light returns, perform self diagnostics on the pcm by turning the screw on the pcm with the key on then read the flashes on the dash, this should give you the # of the trouble code, then get the code chart and diagnose it.