A technical Service Bulliten (TSB) is supplimental information. They usually are issued once some threashold of complaints/warranty work have been done. Usually with problems like this the dealer is calling the coroporate tech support to find a solution. Once a solution that works is determined then a TSB is issued.
If you read the entire text of the TSB it will list out the amount of time to accomplish the job. It also mentions stuff about being covered by warranty, etc.
If you are having the problem described in the TSB you can use the instructions and fix it yourself OR if you lack some tools/skills you can take it in and say "I am having this problem" and hand them a copy of the TSB. If you have a 2000 XJ like your profile says you will have to see how long the warranty covers the problem - 3 years/36,000 or 7 year/70,000 miles.
This might be a good time to develop a relationship with the local dealer. If you indicate you want to use them for service they may be able to do something so it does not cost you. It worth asking....
