Diagnostic check done. Mechanic said it could not scan at all - no codes

Little more detail on WHY it could not be scanned... Was this 'mechanic' experenced and using a professional scanner that's capable of scanning//reading ALL of the control modules?.. Is there a problem with the car that's not allowing scanner communication?? .. There should be trouble codes stored in memory and not a problem to retrieve them with the proper scanner and talent to use it!