As was suggested, adding a PUT (or PUTLOG _ALL_; with SAS 9) will help but then also if the SAS LENGTH for the DATETIME (numeric variable, time in seconds since 1/1/1960 - minimum length of 7, better to be 8 with STORE_CLOCK values) variable is truncated, you will not see evidence of a problem until a subsequent PROC or DATA step, where the variable is referenced.
Another self-initiated desk-checking technique by the OP would be to perform a PROC CONTENTS on the file immediately after the assignment "step", to verify/inspect the SAS NUMERIC variable "length" attribute for the DATETIME variable.
Also, consider that declaring a SAS FORMAT is not the equivalent of declaring a SAS LENGTH (either as a statement or as a keyword for the ATTRIB statement) -- your SAS variable may still be truncated without warning.
Scott Barry
SBBWorks, Inc.
Encouraged SAS system/programming reading:
SAS Language Reference: Concepts, About SAS Date, Time, and Datetime Values
http://support.sas.com/documentation/cdl/en/lrcon/61722/HTML/default/a002200738.htm
SAS Language Reference: Concepts, Numeric Precision in SAS Software
http://support.sas.com/documentation/cdl/en/lrcon/61722/HTML/default/a000695157.htm
Recommended Google advanced search argument, this topic/post:
datetime numeric variable truncated site:sas.com