Car diagnostic code readers have come a long way from what they used to be, let's talk about a little history and catch you up to speed. Code readers, also known as OBD scan stands or automotive scanners are handheld devices that can be plugged into an OBD cable to help diagnose the engine and engine related problems.
Handheld OBD scanners plug directly into a port found directly under the dash of all United States manufactured cars after 1996. These are known as OBDII automobiles, prior to 1996 things were nonuniform and car manufacturers had different methods and readers to diagnose problems. All cars manufactured after the year 1996 were feeded with an OBDII system that allowed a simple universal code reader to help trouble shoot engine related problems. The difference between an OBDI and OBDII system is literally the fact that they now have a universal system to help detect and diagnose car engine troubles.
The introduction of OBDII car diagnostic code readers helped simplify the problem of diagnosing and fixing engine related problems by standardizing the onboard diagnostic system. Allowing for car code readers to output the same 'code' regardless of manufacturer or engine type.
After plugging in an automotive OBDII reader, live data related to your engine and cars performance will appear on the LCD screen of the scanner. This tool can also be used to check the CEL (check engine light) and provide additional information related to the the vehicles fuel injector as well as throttle related information. One of the most important features of the card readers is the ability to check your engines emission status and determine whether its in compliance with state mandated smog emission.
If there happens to be a failure that occurs to the engine and or emission, which is typically related to the o2 sensor, temperature gauge, it will show up and will be recorded to the code readers DTC or diagnostic trouble code. This code is simply an indicator that something in the engine or emission system is faulty. This helps you identify and further determine what exactly is causing the trouble. Keep in mind that this doesn't mean that a part needs to be replaced, rather that it could be a bad sensor or some type of block that is causing the abnormal readings. This helps you find the start of the problem, thus decreasing the time spent with previous car problems.
Car diagnostic code readers can be connected to a serial port of a computer to further determine even more information which can help you better understand where the problem is occurring and how to best combat that. OBD computer diagnostic tools are a must have for any auto owner junkie or shop owner and they typically cost anywhere between $100 - $400. This is very cheap in comparison to replacing parts that do not need to be replaced. Most diagnostic reports offered by auto shops use these standard tools and charge around $100 for an inspection.
There are two types of card readers on the market today, all of which are primarily handheld devices, one which is an OBDI reader and the other that is an OBDII reader. OBDII readers are generally cheaper than OBDII because of the universal capabilities of the readers versus the specialized readers needed in an OBDI auto. For models that are between 1991 - 1995 built by GM, Ford or Chrysler, they created a simple universal standard for the vehicles although these cars have a different type of connector in comparison to other vehicles created with an OBDI type of system.
