Do search engines remove pages from the index for any 400 range status code return?
We are using 400 range HTTP codes to differentiate messaging for different categories of pages when a particular type of content is not found. There are some concerns that this content will not be removed from the search engine indexes as they would be if a proper 404 response is returned.
Has anyone used this method before to return customized error messages that can validate that these other codes are indeed removed from search engine indexes?