Other object storage providers define error codes (or error names) that give more information about the error than the http codes they come with. For example, here is a list of the error codes by some of the other providers:
So if you look for an object and it doesn't exists, Azure will give you this error:
I haven't been able to find if there is something like this for Openstack or specifically Bluemix.
Do they also have error codes apart from the http status codes?
If you don't have access to SWIFT/Bluemix logs, unfortunately, you will have only the status code to help you.
However, Swift is pretty precise on its status code and most of the time you only need it to solve your problema.
If you're dealing with a specific situation, you can ask here and may be someone can help you.