Documentation regarding the activation or adjustment of the OBJWAIT parm in SharedPrefix.PARMS(JCLDEFC) or Prefix.PARMS(JCLDEF) is not indicated in the PIOM guide.
If you are using Complex parms yes and activate OBJWAIT. You need to run any of the JCLGEN jobs to activate in the Complex. Running JCLGENUC to regenerate JCLGENUC will accomplish this.
The next thing you need to do is run any JCLGENx for each Unit in that Complex. Submitting JCLGENU to regenerate JCLGENU will accomplish this. Unlike most Complex parms the changes to OBJWAIT are NOT pushed to the UNIT(s) thus requiring you to run a JCLGENx for each Unit.