80 models with feed back carbs did not use a scan tool.. 81 and 82 models did.84 to 95 models use scan tools.. starting in 94.. some model cars use OBD1.5 that could have a obd1 connector or an OBD2 connector.. i normally have problems with the other models of 1995 as OBD2 consumer scan tools don't all work with them.. 96 and up models use OBD2 scan tools.. scan tools are needed to work on and understand what's going on with your fuel injected C3 and C4.. corvette..the 96 and newer cars are OBD2.. so scan tools are easy to get for them.. first... this is your ALDL connector you can use a jumper wire or even a paper clip to connect the A and B terminal then turn the key on and count the flashes of the check engine light.. it will always flash a code 12.. to show that the computer is working.. and that the engine is not running.. some of the following are outdated and not covered/supported by their manufacturers any more. this is a monitor 2000 from OTC... these are available used once in a while.. with the proper cartridge and cables.. they can give you live data on models from 81 to 89... they do NOT work with any cars newer than 89... this was the Professional scan tool that even GM used when they came out.. and can be had really cheep.. sometimes under 100 bucks.. with cartridges and cables.. if you have 89 and earlier models of GM / ford / chrysler.. this is an option.. this is an early Autoxray unit.. they cover cars back to 1982.. through 95 .. as long as it has the proper cable.. there are several versions of this... i have one of these.. and it worked great.. until a ford with shorted wires let the smoke out of it.. this is an Actron CP 9110... with the GM cartridge and cable.. it will cover from 82 though 94/95 models i have heard that there is an OBD2 cable and cartridge for these.. i have never seen one.. i have one of these with a GM set up and the ford set up.. it works great.. this is the OTC monitor 4000... there are a bunch of versions.. you might want to steer clear of the straight monitor 4000 version that does not have removable wires from the top.. most of those were traded in.. for a 4000E.. with the removable wiring right at the top of the unit.. the newer versions were monitor 4000E.. monitor extended.. extended monitor, monitor elite.. as long as they have the removable connector from the top.. its a go.. try to get them that have the correct cables and cartridges for your car... i just picked up one with a 3 sets of cables.. domestic early.. asian import and OBD2 for 300 bucks.. if you have a 82 to 95.. this is probably what you should look for if you are on a budget.. one thing.. cartridges can be had on B bay along with cables.. but if you pick up a bare unit.. its going to cost you.. shop carefully... this is the snap on tools MT2500... again this is a professional version.. snap on does not support these any more as far as i know... and Everything was expensive on them.. i have seen these as cheep as 200 bucks and upwards of 1,400 for truly loaded versions.. if the one you are looking at has the cartridges and cables you need.. that might make it a great buy.. this is an OTC genisys.. there are early models available that work great.. do all kinds of things.. the monitor 4000E cables work with them usually.. again.. cables have to match your car... and the software installed also.. now... if you are looking at the scan tools in most parts stores. in the 300 to 500 dollar range... they don't hold a candle to this one... if you want a new scan tool... this is the OTC 3499N kit.. i have seen them for 450 bucks to 700 bucks.. they will work on 82 up domestic cars... and also cover your 2012 daily driver.. ###########################################on 96 and newer corvettes, and cadillacs with the automatic temp control.. you can sometimes retrieve codes and data by pushing the OFF and the warmer buttons on the AC control panel.. but codes WILL NOT let you diagnose a cars problems.. caddys had this feature back in 1983.. there are on the temp control buttons the ability to read live data on the 96 and newer corvettes.. hold the off and warmer buttons on.. the warmer button is sometimes an UPward pointing arrow.. after you turn the key on.. after 5 seconds of holding them.. all the dash lights should come on.. release.. make sure that your foot is NOT on the brake pedal.. codes will show up on one of the displays.. there is another button sequence to push for other options.. ###############################they only aim you at a circuit that is out of spec.. could be the sensor.. the wiring.. the connector.. or something else that effects that circuit reading.. this is what the scan tools show.. this is a slight variation on the chart... that actually has the right hand column that tells you what section to turn to in the factory service manual... i know that none of this makes sense to you.. its a learning process.. i drop through the active posts forum daily looking for new posts... so if you have problems.. try to access the codes.. post them with the year.. make and model and your description of what the car is doing ... do this in a new post.. forum members may try to help..
its third and long.. yep.. he is going to punt it.. just to make it easier to find..
Wayne, I PM'd you