There are a number of tools you can use for WSUS troubleshooting and testing.

1. The first one is available on all clients, as it’s a client based tool – wuauclt.exe
   
   The following are a list of options.

   /DetectNow
   /ReportNow
   /RunHandlerComServer
   /RunStoreAsComServer
   /ShowSettingsDialog
   /ResetAuthorization
   /ResetEulas
   /ShowWU
   /ShowWindowsUpdate
   /SelfUpdateManaged
   /SelfUpdateUnmanaged
   /UpdateNow
   /ShowWUAutoScan
   /ShowFeaturedUpdates
   /ShowOptions
   /ShowFeaturedOptInDialog
   /DemoUI

   If you copy this to a text file and save it as *.bat, when run on a client machine, it will reset WSUS settings on the client machine and force it to check now for updates. This will speed up the checking process drastically.
   You will need reg.exe if you are running this on an old machine, e.g. Windows XP or Windows Server 2003.

   @echo on
   xcopy \\comutername\wsustools\reg.exe %windir%\system32 /Y
   net stop wuauserv
   REG DELETE "HKLM\Software\Microsoft\Windows\CurrentVersion\WindowsUpdate\Auto Update" /v LastWaitTimeout /f
   REG DELETE "HKLM\Software\Microsoft\Windows\CurrentVersion\WindowsUpdate\Auto Update" /v DetectionStartTime /f
   Reg Delete "HKLM\Software\Microsoft\Windows\CurrentVersion\WindowsUpdate\Auto Update" /v NextDetectionTime /f
   Reg Delete "HKLM\Software\Microsoft\Windows\CurrentVersion\WindowsUpdate\Auto Update" /v UnableToDetectTime /f
   Reg ADD "HKLM\Software\Microsoft\Windows\CurrentVersion\WindowsUpdate\Auto Update" /v AUState /t REG_DWORD /d 2 /f
   net start wuauserv
   wuauclt /detectnow
   exit

2. Another tool on the client you can use the Microsoft client diagnostic tool – http://download.microsoft.com/download/9/7/6/976d1084-d2fd-45a1-8c27-a467c768d8ef/WSUS%20Client%20Diagnostic%20Tool.EXE

   Download and install on the client, then run the ClientDiag.exe tool, this will display a number of PASS/FAIL results in a comment prompt.

   Very handy tool to use to test the URL of WSUS either HTTP or HTTPS.

3. The other tool you can use is server based, it is called WSUSutil.exe. WSUSutil.exe is located in the %drive%\Program Files\Update Services\Tools folder on your WSUS server

   More information can be found here – http://technet.microsoft.com/en-us/library/cc720466(WS.10).aspx

4. Another troubleshooting tip is to check the c:\Windows\WindowsUpdate.log file on the client, this has a running log on all Windows Update events.