You’ve been driving around town for the last three months or so and every once in a while the Check Engine Light has been going on and off with no rhyme or reason. It’s very possible this is the reason why your gas mileage has dropped through the floorboards. Now that gas is over $2.00 a gallon, you figure it’s time to find out what the problem is. So you drive over to see Franz, your favorite mechanic from the old country.
He takes a quick under the hood and says he has to hook up his scan tool to see what’s going on. He tells you that it will run about $100.00 to hook it up and diagnose the problem. Of course that’s just the diagnosis; any repairs will be extra. You think to your self, “Self, maybe we should try to do this on our own”.
First thing you are going to need is a scan tool. With so many choices and price ranges you will need to do some comparing and decide which one you will need. You can get a simple code reader, like the Equus Products, Inc 3145 Digital Ford Code Reader all the way up to the professional OTC Mind Reader OBD II Diagnostic Scan Tool. You can also get an interface tool, such as the Winsted Group Inc. OBD-II Interface, which will allow you to use your laptop as a scan tool. Most of these are easy to use even though most of the manuals are sorely lacking. But if you have learned to us a computer, you should be able to learn your scan tool fairly quickly and easily.
Personally, when it comes to electronics, I always get more than I need since the more I use it; the more I grow into it.
For this article I used the Autoxray Ez-Link Pro Pack. It is fairly typical of all scan tools and the connections and procedures are similar to all the other scan tools.
Before buying any scan tool, make sure it will work on your vehicle. Make sure it has the right cables and protocols for your system. Scan tools are constantly being upgraded so the one you buy may be one that will need to be upgraded. For instance, the late model Ford Motor vehicles use a special signal protocol called DCL and unless your scan tool can read it all you will get are DTC’s and maybe some other diagnostics. You will not be able to see any switch or sensor signals.
Another thing to keep in mind is that some domestic vehicles such as the Eagle Talon, Ford Probe and Chrysler Sebring are Japanese made and operate on Japanese power trains. You will need special adapters to get any data from these systems and they will cost extra. You may not be able to get as much sensor and switch information as the domestic systems in the earlier models, but as they got newer, more information has become available.
The basic Auto X-Ray scan tool just gives you information. But it does that very well on GM, Chrysler and Ford, including DCL, that may be all you need. The OTC and SunPro scan tools can test some of the actuators. This means that when put into a special test mode, you can, with the engine off, actuate relays, solenoids, switches and fuel injectors. Auto X-Ray chose not to include this feature due to safety concerns for new users because in this mode it is possible to inadvertently start the engine. But if you have the applicable Chrysler product and you are certain you can handle the safety issues, you might prefer one of the testers with this capability.
You will also need the factory service manual or CD, or an Online service such as Alldata DIY. This will provide you with sensor reading specifications, and their locations. Also there are wiring schematics if you have track down a bad connection in a sensor or switch circuit.
