The system reads OBD errors and information you need to know

Have you ever come across the term OBD and do you understand anything about it? This is a feature of car computers and has a little-known history. Today, let CarOn compile useful information about OBD devices for you!

What is OBD error reading system?

OBD stands for On-Board Diagnostics. Simply put, an OBD system is an integrated computer that communicates with other systems, including ECU, TCU, etc. It monitors ignition system performance, engine performance, transmission operation gear, emissions system activity, etc. Based on feedback from sensors around the vehicle, the OBD system determines whether everything is working properly or if something is starting to go wrong. It’s advanced enough to warn drivers before serious problems occur, often the first sign of a faulty part.

Operating principle of the OBD system

When the OBD system identifies a problem, it turns on a warning light in the dashboard (usually the Check Engine Light), then stores a trouble code (known as a DTC or diagnostic trouble code). A mechanic can connect the scan tool to the OBD II connector under the dash and read this code. This provides the information needed to begin the diagnostic process. Note that reading the code doesn’t necessarily mean the mechanic immediately knows what happened, but the mechanic has a place to start looking.

History of formation and development

The history of OBD readers dates back to the 1960s. Several organizations laid the foundation for the standard, including the California Air Resources Board (CARB), the Society of Automotive Engineers (SAE), the International Standardization (ISO) and Environmental Protection Agency (EPA). The formation and development stage of OBD goes through each year as follows:

1968 — Volkswagen introduces the first OBD computer system with scanning capabilities

1978 — Datsun introduces a simple OBD system with limited capabilities that are not standardized

1979 – The Society of Automotive Engineers (SAE) recommends a standardized diagnostic connector and set of diagnostic test signals

1980 – GM introduces a proprietary interface and protocol capable of providing engine diagnostics via the RS-232 interface or simply by flashing the Check Engine Light

1988 — Standardization of integrated diagnostics introduced in the late 1980s following a 1988 SAE recommendation requiring a standard connector and diagnostic kit

1991 – The state of California requires all vehicles to have some form of basic on-board diagnostics. This is called OBD I

1994 — The state of California requires that all vehicles sold in the state beginning in 1996 have SAE-recommended OBD — now known as OBDII. This stems from the desire to perform widespread emissions testing. OBDII includes a series of standardized diagnostic trouble codes (DTCs).

1996 – OBD-II becomes mandatory for all cars manufactured in the United States

2001 – EOBD (European version of OBD) becomes mandatory for all gasoline-powered vehicles in the European Union (EU)

2003 – EOBD becomes mandatory for all diesel vehicles in the EU

2008 — Beginning in 2008, all vehicles in the United States are required to implement OBDII through the Controller Area Network as prescribed by ISO 15765-4

Structure of OBD machine

A basic OBD system consists of a central system, a network of sensors, a connection point and indicators, creating a complete monitoring system with standardized access and readability. . The OBD system includes the following components:


The central part of the OBD system is the Electronic Control Unit, or ECU. The ECU collects input from various sensors throughout the vehicle. The ECU then uses this data to control vehicle components, like fuel injectors, or monitor problems.


There are sensors throughout the vehicles covering every area from the engine and chassis to the electronic systems themselves. Each of these systems sends a code to the ECU, specifying the source and parameters of the signal. The ECU then “reads” and interprets this signal.


If a sensor sends information to the ECU that is out of normal range, the ECU will store the information as a code called a Diagnostic Trouble Code or DTC. A DTC code is essentially a list of letters and numbers, indicating the origin and nature of the problem. DTC codes are usually standardized but may be manufacturer-specific. Once the DTC is saved, the ECU will send a signal to your indicator to notify you that a problem has been found. The DTC can also be pulled by linking the sensor to the connector of the OBD system.


When the ECU collects the DTC code, it sends a signal to the vehicle’s dashboard to turn on the appropriate warning lights. These lights, officially known as Malfunction Indicator Lights or MILs, provide an early warning system for vehicle problems. In general, if the light is on and stays on, the problem is minor. If the light flashes, the problem is urgent.


All data and DTC codes collected by the ECU can be accessed through the Diagnostic Link Connector or DLC. The DLC port is the access point of vehicles with OBD systems and is typically found below the dashboard on the driver’s side, although it may be located elsewhere in commercial vehicles. Current vehicles are built with a standard OBDII system so that any scan tool with a type 2 cable can connect to a type 2 connector.

Benefits of OBD system

Perhaps the most widespread use of OBD is in the vehicle industry, as careful vehicle maintenance is an important aspect of this industry. Commercial vehicle companies have widely deployed the use of advanced scan tools for OBD2 systems, especially because of the following benefits that OBD-II brings:

Quick diagnosis

With standardized connectors and DTCs, as well as a detailed DTC system through SAE J1939, commercial vehicle problems can be identified in just minutes. By simply connecting a scan tool to the gateway, technicians can obtain valuable diagnostic information that can be used to identify and resolve problems before they become costly repairs.

Verified information

With an OBD system, information is collected through the use of sensors rather than by human technicians. This increases the accuracy of the information retrieved, reducing the likelihood of missing serious system errors.

Various figures

OBD systems can be used to collect a variety of metrics beyond those related to vehicle maintenance. OBD systems can monitor driver behavior to ensure that the driver is following legal requirements as well as company protocols. The systems can also be used to broadcast metrics over a secure line, allowing central control to easily monitor drivers and their vehicles from a remote location.

Improve compliance

As of 2010, standards set by the EPA and the Clean Air Act also apply to heavy-duty engines used in trucks over 14,000 pounds. Vehicles operating in some states need to be inspected regularly to ensure that they comply with these standards. OBD systems monitor emissions to ensure that vehicles always meet minimum requirements. They also warn users when emissions exceed allowable limits so the problem can be addressed and rectified prior to inspection.

Cut the cost

Between faster, more accurate diagnostics, expanded monitoring capabilities and improved vehicle compliance, OBD systems have helped commercial vehicle companies reduce costs.

Although the above benefits of OBD are impressive, commercial vehicle manufacturing companies as well as auto garages can use this tool to optimize maintenance processes as well as increase vehicle value. a little bit.

What are the applications of OBD?

OBD is commonly used on many types of vehicles as an easy way to diagnose vehicle problems. However, OBD applications have expanded to cover more specific areas of vehicle monitoring and maintenance, especially in the past few years. Some more specific applications of OBD include:

Monitor driver behavior

Automotive-related industries are increasingly using OBD systems as a way to monitor driver behavior. For example, some auto insurance companies offer reduced premiums to drivers who use vehicle data recorders to demonstrate that they demonstrate safe driving practices. Additionally, companies could install similar data loggers in their fleets or delivery vehicles to track driver behavior in real time, which could help reduce liability. their rights in case of an accident or traffic violation.

Check exhaust gas

OBD-II testing is now a common method of checking the emissions of vehicles in areas of the United States that require it. As part of the OBD-II standard, these systems closely monitor emissions, so testers can simply use a scan tool to check for emissions-related trouble codes to ensure ensure that the vehicle is compliant.

Additional equipment

Car enthusiasts and professional drivers often use OBD systems to monitor metrics that are not typically displayed on standard vehicles. These metrics can be displayed on custom settings in the vehicle or broadcast to the driver’s phone.

Commercial vehicle telematics

Commercial vehicle companies often use what is called Generic OBD II to gather information about their vehicle fleets. This includes fleet tracking, fuel efficiency monitoring, driver behavior monitoring, remote diagnostics, etc.

As one of the units using OBD machines in the repair and maintenance process, CarOn hopes that the above useful information will help readers have a more general view of the OBD system.

For further information, please contact hotline 0961.247.360 or via website: for detailed instructions and advice.

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