Mazda Repair: Scan Tools, obd ii, data streams

Question
Hi Chris,
I have a check engine light on.  I want to purchase a code reader or scan tool to find out what the problem is.  The scanners seem to cost quite a bit more than code readers.  Are they worth the money?  What is the differance between the two? The advertisement for scan tools say they will provide live engine data?  What exactly is that?  Is there any system beyond OBD II that some code readers will not work on?
Thanks,
George


Answer
Hi George thanks for asking,
A scanner is worth buying if you repair alot of vehicle, the scanner will show you Data streams on sensors, and it gives you alot of control over the vehicle over the scan tool, the code reader will only retrieve and erase trouble code stored on the PCM,
Good Luck
Chris P