On-Board Diagnostics: A Simple Summary


The logic underlying an automobile’s on-board diagnostic system, also known as the OBD, is remarkably simple. After connecting an OBD system to your automobile, you will receive an immediate summary of its current or potential mechanical problems. This technology proves to be an invaluable resource for professional automotive repair persons, significantly reducing the amount of time it takes to investigate the source of a mechanical issue. However, OBD devices are not exclusively offered to professional mechanics. Most OBD systems are available for purchase at any ordinary automotive store. If you are interested in learning do-it-yourself methods for car and truck repair, installing an on-board diagnostic system may be the first step in this process.

Before purchasing an OBD device, it is first necessary to consider the year and make of your vehicle. For example, only cars and trucks manufactured after 1996 use today’s standard version of the OBD system, known as the OBD-II. If you want to be certain that your automobile is compatible with the OBD-II, check under the hood; here, you are likely to find a sticker that verifies your car or truck’s OBD-II compatibility. Additionally, some motor companies require even more precise OBD protocols; Ford, for instance, uses a version of the OBD-II known as SAE J1850 PWM. Although the variety of these distinctions may appear intimidating, the specific requirements of any vehicle should be available in the handbook provided by its manufacturer. For this reason, it is important to consult your handbook before choosing an OBD system.

After locating and purchasing the right OBD device for your vehicle, the setup process for your new product is not particularly difficult. To begin with, the scanner must be plugged into your vehicle’s OBD-II connection site. In most cases, the location of the OBD site is easy to discover. This connector should be a maximum of three feet from the driver’s seat, and no tools are needed to uncover its location. The connecting site is usually shaped like a trapezoid, containing two rows of square openings that number one through fifteen. Given its close proximity to the driver’s seat, the site is often inside or near the dash or ash tray.

Once connected, the OBD device will function in two possible ways. For some OBD devices, it may be necessary to connect your OBD scanner to a laptop computer using a USB cable. Moreover, you will need to download OBD software—which should accompany your purchase of the scanner—in order to establish communication between the scanner and your computer. Next, the laptop will display the error codes discovered for your vehicle. Alternatively, today’s preferred diagnostic method involves an all-in-one OBD code reader. In order to use this device, you simply connect the code reader to your car or truck’s connection site. The error codes for your vehicle will then display directly on the screen of the device.

Once you have received your vehicle’s diagnostic trouble codes, you must discover the meaning of each individual readout. The first digit will be a range of four letters, each corresponding to a different component of the automobile: powertrain, body, chassis, or undefined. The second digit will determine the specificity of the problem. If the number is 0, the issue is a general malfunction applying to all vehicles; if it is a 1, the problem is specific to the vehicle’s manufacturer. Next, the third digit—ranging from 0-9—describes the sub-system related to the code; 7 and 8, for example, signify a problem with the transmission. Finally, the fourth and fifth digits are the most variable and distinct of the five, describing the exact issue discovered within the sub-system of the vehicle. Your code reader should include a manual that provides the precise meaning of each code. After displaying these error codes, the OBD’s function is complete. Once equipped with the knowledge provided by the OBD, you are now fully prepared to address the problem.

Comments are closed.