Slick 60's

Anyone know anything about OBD 2 scan tools? What is the difference with buying a cheap one ($30) and an expensive one ($200)? Other than displaying the error codes, what can these scan tools do? Will they work on Fords, Dodges and Chevys?

I don't know but if you have a laptop, you may find something that does the same thing better, for less.
For instance, I use the following 2 programs for my '88 firebird (obd1).
http://winaldl.joby.se/
http://www.tunerpro.net/
With them, I can see the voltage of any sensor the computer sees, and they convert the voltages to meaningful information - coolant temp, manifold absolute pressure, o2 readings, injector pulse width, and etc. I can see error codes and reset error codes - no more disconnecting the battery for 5 minutes. I can data log with both programs. Tuner pro allows playback of the log.
The programs are free. I already have a laptop. I had to buy a $60.00 cable.
So far they've helped diagnose a couple problems. Tunerpro, as the name suggests, has tuning capabilities, though additional hardware is required. I'm going to start tweaking it soon to better understand efi in preparation for installing efi on the truck.

I'm sure there's something like that for obd2

Biggus
OBIT II was required to be installed in all vehicles sold in the US in 1996.
All makes and models are required to have it.
You'll find tons of these tools for sale everywhere from advance auto parts to walmart to include ebay. the price will dictate what the tool will do.
the less costly one will only give you the code number then you'll have to look it up in the manual or cd and my or may not erase the code.
the mid range ones will tell you the code number and a description of the problem and will erase the code and are upgradeable via the internet(costs$$$$)
these scanners will only read engine management and drivertrain issues not ABS or air bag trouble codes.
the high dollar ones are usual bought by repair shops.
If you are going the read codes in 2007 and up vehicles made sure it is CAN compatible- if not it may not read all the codes.
I like the ones that tell you the code and a description of the problem
Hope his helps. Brian

I use an Actron CP9125

It costs about 60 bucks and will scan and basic diagnose.

It also clears all codes hard and soft.

Garbz

all you really need is the codes and be able to clear the codes. I have the cheapest one i could find and it works great. Some of the other expensive ones will do stuff you probley won't need espically if you have access to google the codes. just my

Garbz wrote:I use an Actron CP9125

It costs about 60 bucks and will scan and basic diagnose.

It also clears all codes hard and soft.

Garbz

This.
I have an Actron, very happy with it. Totally easy to use. You can buy them on Amazon pretty reasonable.