The IEC602I explanation in the manual says (with emphasis added by me):
text is
[VTOC NOT CONVERTED ON dev,ser,cde]
[VTOC NOT CONVERTED ON dev,ser,0,
,(EXTENT=cchh,DSCB=cchhr-cchhr)]
[VTOC NOT CONVERTED ON
dev,ser,cde, ,(EXTENT = cchh,DSCB =
cchhr)]
When the system tried to allocate DASD space on volume ser on unit dev, the volume table of contents (VTOC) conversion routine entered, but failed to convert or repair the VTOC.
In the message text:
dev The device number of the specified device.
ser The volume serial number.
cde The code.
If the message received matches the first variant of IEC602I, then the value of cde indicates the reason VTOC conversion failed.
Cde 1C There were insufficient DSCBs available to rebuild the free space chain. The VTOC is full.
Cde 1D An I/O error occurred.
If the message received matches the second variant of IEC602I, then either the same DASD track or set of tracks are allocated to multiple data sets, or Format 3 DSCBs are incorrectly chained, which can make it appear that the same track or set of tracks are allocated to multiple data sets. This condition can occur if a prior Data Facility Data Set Service (DFdss) defrag operation was abnormally terminated. This can be identified by the existence of a data set on the volume whose name is 'SYS1.DFDSS.DEFRAG.xxxxxxxx, where xxxxxxxx is eight bytes if 'FF'X. For this variant, in the message text:
EXTENT=cchh
Specifies the first track that appears to be multiply allocated.
DSCB=cchhr-cchhr
Specifies a range of DSCB addresses. Within this range is one of the DSCBs that contains the multiply allocated track(s).
So you need to check for a SYS1.DFDSS.DEFRAG.xxxxxxxx on the volume and if there is then do the DEFRAG again. If there's no data sets on the volume, I would use ICKDSF to INIT the volume again. If there are data sets on the volume, move them off and then INIT the volume again.
