CDR file names have the following format/structure: Position 1-4: Data year. Position 5: Data program. "1" is for CISS. Position 6-8: Three digit PSU number. Position 9-11: Sequential Case Number for PSU. Position 12: Embedded underscore as separator. Position 13,14: Vehicle Number Position 15-18: OPTIONAL. File type. ACM=Air bag Control Module. PCM=Powertrain Control Module.