You’ve probably heard the term on-board diagnostics and telematics before, but you may not be too familiar with what it is and why it’s important.

On-board diagnostics, fortunately, is not that complicated. If you’re interested in learning more about the history of on-board diagnostics and what it is, keep reading.

What is On-Board Diagnostics?

On-board diagnostics refers to a car’s ability to self-diagnose and report problems that arise. Drivers and technicians can then use this information to ensure that the vehicle gets the right care to solve the problem.

As can be expected, OBD systems have become more advanced and made more readily available. Over time, there have been a few different OBD systems that vary in how much information they provide and how advanced they are. 

Here’s a brief history of the previous and existing OBD systems.


Assembly Line Diagnostic Link (ALDL) is widely considered the start of OBD systems. It had different interfaces and could change power train control modules. The first few models used 160 baud rates, while later versions of ALDL could have up to 8192 baud rates. 


OBD-I vehicles are more advanced than simple ALDL ones but less advanced than many of the OBD vehicle systems we know today. Depending on the manufacturer, an OBD-I system will have more or less advanced features.

Each manufacturer uses its own diagnostic link connector that can then be connected to different pins. Once these connections are made, a series of codes blink out a number corresponding to a more specific problem.

A simple “check engine” light, for example, will appear the same every time, but when a technician reads the OBD, the two-digit number that appears will help them determine the specific problem that the engine is having.

OBD 1.5

Although not a full update to the existing OBD system, OBD 1.5 was the next step forward in OBD systems. It was used by General Motors between the years of 1994 and 1995 and was cataloged as either OBD-I or OBD-II at the time. 

OBD 1.5 included some new or different codes for certain vehicle models and changed the ALDL connections and pins. However, the biggest change was the necessity of a scan tool to read the codes generated by the system.

Before OBD 1.5, some systems used scan tools, and some did not. With the implementation of OBD 1.5, though, a scan tool was necessary to read the codes.


Compared to OBD-I, OBD-II is improved in standardization and capability. The standard OBD-II specifies the diagnostic connector and the corresponding pinout, has electrical signal protocols and includes a messaging format.

The scan tool for OBD-II is connected to the vehicle’s battery, eliminating the need for a separate power source, though some technicians do still choose to use a separate source. This is helpful if the vehicle loses electrical power.

OBD-II was created to meet emissions requirements, and while it only emits emissions-related codes, most manufacturers have expanded its ability to be the only data link connector in the vehicle. This means that it is the only system that diagnoses the vehicles.

Another change between OBD-I and OBD-II is that the OBD-II system has a code change. Trouble codes are written with four digits and are preceded by a letter indicating the problem’s location.


OBD-II systems are ever-changing and adapting to make diagnostics easier to understand and more accurate. With each update, OBD systems are expanded to include more possible problems, making it easier for technicians to locate and solve a vehicle’s malfunction.

The Morey MCX1M1 is OBD-II plug and play tracker with a focus on easy integration and set up. Featuring GNSS, 4G LTE (CAT M1), and Bluetooth connectivity, it is excellent for light vehicle tracking in applications such as car rental, courier delivery service, insurance telematics and more. Additionally, the MCX1M1 can also read OBD-II data from the on-board computer, supporting firmware and configuration updates via Bluetooth.