On-board computer systems have been around for close to thirty years now, and more and more folks are looking for a way to check out their own vehicle when the dreaded "Check Engine" light comes on. In most cases a code reader or scanner is required to find out why the light came on. In the USA any vehicle sold within the US after 1996 was required to be equipped with OBDII diagnostics and for good reason. Until this date almost every vehicle manufacture required a dedicated scanner or at the very least, specialized cable to link into the computer system. With OBDII, any OBDII capable code reader or scanner would work on any vehicle. Besides the "generic" codes and data, manufactures were also allowed to have manufacture specific systems, and with these systems, most required a more sophisticated scan tool in order to read and properly diagnosis what may be at fault.

One misconception that I see alot of is folks buying a code reader or scanner and not realizing that the powertrain computer will be the only system that the tool will work on. There are several computers on todays vehicles such as the ABS, SRS, Suspension, Steering, Body and Climate control. These systems do not usually fall under the OBDII system and a scanner or code reader will be required that is capable of diagnosing a fault within these systems. Keep in mind that these tools are extremely pricey and often the updates can cost upwards of $1000.00.

If you in the market for a code reader or scanner ask yourself what you want the tool to do for you. If you merely want to check the powertrain for codes and your vehicle is 1996 or newer, look for a brand name code reader and you should be set. If the vehicles you will be checking include prior than 1996 models, you will need to make sure that the code reader or scanner will test the vehicles that you have. What I mean is make sure that the required software and cables are included. Prior to 1996 would be considered OBDI.

Code readers work fantastic for reading the fault code and turning off the Check Engine light. A scanner will do this as well plus give you detailed data stream (sensor readings, etc) information. One last thing I want to mention is what is coming and in some cases is already here.. CAN. CAN (Controller Area Network) is the future and has been installed/tested on several models that are on the road today. It would be a good idea to look for a code reader or scanner that is CAN equipped so your investment will not become obsolete. Code readers and scanners are available PC based to be used with a laptop, PDA based to be used with a PDA device including some phones. A stand alone system will come with everything required to perform the task. There are some great deals on ebay.. just be sure to ask questions and make certain what you are looking at will fit your needs and do what you want it to do.

Bruce Bonebrake

ASE Master Automotive Technician