TW> The CEL light is more of a Engine Computer Check system. The smog device   
   TW> monitiring is jsut an add on. My now gone Chev S-10 even had the   
   TW> automatic transmission monitored by the CEL system   
      
   Yes, it monitors all types of sensor related data.     
      
   I have one of those code readers, but also have the cable/software laptop   
   setup that can give me way more information.  In addition to that, I also have   
   an anti-lock brake diagnostics that can plug into the same OBD connection.   
      
   I have used the anti-lock reader many times to figure out what was causing my   
   several anti-lock break errors that I have seen over the years.  It is always   
   a "speed sensor", but the trick is knowing which wheel/hub has the issue.  It   
   is a complete guessing game without this tool.     
      
   It will tell you which one is bad, and then you have to replace the wheel/hub   
   since it is an enclosed unit.   
      
   - Mark   
      
   --- WWIVToss v.1.50    
    * Origin:  http://www.weather-station.org * Bel Air, MD -USA (1:261/1304.0)