You may have come across the terms “OBD” or “OBDII” when reading about connected vehicles and devices like the Geotab GO. These features are integral parts of modern car onboard computers and have a history that’s not widely known. This article provides a comprehensive overview of OBDII and a timeline of its development.
What is OBD (On-Board Diagnostics)?
On-Board Diagnostics (OBD) refers to the automotive electronic system that provides vehicle self-diagnosis and reporting capabilities for repair technicians. An OBD system allows technicians to access subsystem information to monitor performance and diagnose repair needs.
OBD is the standard protocol used in most light-duty vehicles to retrieve vehicle diagnostic information. This information is generated by Engine Control Units (ECUs), also known as engine control modules, within a vehicle. Think of them as the car’s computers or brain.
Alt text: OBDII port located under the dashboard on the driver’s side of a vehicle, used for connecting diagnostic tools.
Why is OBD So Important?
OBD is a crucial component of telematics and fleet management as it enables the measurement and management of vehicle health and driving behavior.
Thanks to OBD, fleets can:
- Track wear and tear trends and identify vehicle parts that degrade faster than others.
- Instantly diagnose vehicle issues before they escalate, supporting proactive rather than reactive maintenance.
- Measure driving behavior, speed, idling time, and much more.
Alt text: Car mechanic using an OBD2 scanner tool to diagnose vehicle problems by connecting to the OBDII port.
Where is the OBDII Port Located?
In a typical passenger vehicle, the OBDII port is usually found on the underside of the dashboard on the driver’s side of the car. Depending on the vehicle type, the port may have a 16-pin, 6-pin, or 9-pin configuration.
What is the Difference Between OBD and OBDII?
Simply put, OBDII is the second generation of OBD or OBD I. OBD I was initially connected externally to a car’s console, whereas OBDII is now integrated within the vehicle itself. The original OBD was in use until OBDII was developed in the early 1990s.
History of OBDII
The history of on-board diagnostics dates back to the 1960s. Several organizations laid the groundwork for the standard, including the California Air Resources Board (CARB), the Society of Automotive Engineers (SAE), the International Organization for Standardization (ISO), and the Environmental Protection Agency (EPA).
It’s important to note that before standardization, manufacturers created their own proprietary systems. Each manufacturer’s tools (and sometimes even models from the same manufacturer) had their own connector types and electronic interface requirements. They also used custom codes to report issues.
Key Milestones in OBD History
1968 — Volkswagen introduced the first computer-based OBD system with scanning capabilities.
1978 — Datsun introduced a simple OBD system with limited, non-standardized capabilities.
1979 — The Society of Automotive Engineers (SAE) recommended a standardized diagnostic connector and a set of diagnostic test signals.
1980 — GM introduced a proprietary interface and protocol capable of providing engine diagnostics through an RS-232 interface or, more simply, by flashing the check engine light.
1988 — Standardization of on-board diagnostics gained momentum in the late 1980s following the 1988 SAE recommendation calling for a standard connector and diagnostic set.
1991 — The state of California mandated that all vehicles have some form of basic on-board diagnostics. This became known as OBD I.
1994 — The state of California mandated that all vehicles sold in the state from 1996 onwards must have OBD as recommended by SAE, now termed OBDII, to enable widespread emissions testing. OBDII included a series of standardized Diagnostic Trouble Codes (DTCs).
1996 — OBD-II became mandatory for all cars manufactured in the United States.
2001 — EOBD (the European version of OBD) became mandatory for all gasoline vehicles in the European Union.
2003 — EOBD became mandatory for all diesel vehicles in the EU.
2008 — From 2008, all vehicles in the United States are required to implement OBDII via a Controller Area Network as specified in ISO standard 15765-4.
What Data Can You Access from OBDII?
OBDII provides access to status information and Diagnostic Trouble Codes (DTCs) for:
- Powertrain (engine and transmission)
- Emission control systems
Additionally, the following vehicle information can be accessed via OBDII:
- Vehicle Identification Number (VIN)
- Calibration Identification Number
- Ignition Counter
- Emission Control System Counters
When you take your car to a service center, a mechanic can connect to the OBD port with a scan tool, read fault codes, and pinpoint the problem. This means mechanics can accurately diagnose issues, quickly inspect vehicles, and fix any faults before they become serious problems.
Examples:
Mode 1 (Vehicle Information):
- Pid 12 — Engine RPM
- Pid 13 — Vehicle Speed
Mode 3 (Trouble Codes: P= Powertrain, C= Chassis, B= Body, U= Network):
- P0201 — Injector Circuit Malfunction – Cylinder 1
- P0217 — Engine Overtemperature Condition
- P0219 — Engine Overspeed Condition
- C0128 — Brake Fluid Low Circuit
- C0710 — Steering Position Malfunction
- B1671 — Battery Module Voltage Out of Range
- U2021 — Invalid/Faulty Data Received
OBD and Telematics
The presence of OBDII allows telematics devices to silently process information such as engine RPM, vehicle speed, fault codes, fuel consumption, and much more. The telematics device can use this information to determine trip start and end, over-revving, speeding, excessive idling, fuel usage, etc. All of this data is uploaded to a software interface, enabling fleet management teams to monitor vehicle usage and performance.
With the multitude of OBD protocols, not all telematics solutions are designed to work with every type of vehicle currently on the road. Geotab telematics overcomes this challenge by translating diagnostic codes from different makes and models, and even electric vehicles.
Using the OBD-II port, you can quickly and easily connect a fleet tracking solution to your vehicle. In the case of Geotab, it can be set up in under five minutes.
If your vehicle or truck does not have a standard OBDII port, an adapter can be used instead. In any case, the installation process is quick and does not require any special tools or help from a professional installer.
What is WWH-OBD?
WWH-OBD stands for World Wide Harmonized On-Board Diagnostics. It is an international standard used for vehicle diagnostics, implemented by the United Nations as part of the Global Technical Regulation (GTR) mandate, which includes monitoring vehicle data such as emissions output and engine fault codes.
Advantages of WWH-OBD
Below are the advantages of moving to WWH in more technical terms:
Access to More Data Types
Currently, OBDII Parameter IDs (PIDs) used in Mode 1 are only one byte, meaning only up to 255 unique data types are available. The expansion of PIDs could also be applied to other OBD-II Modes that have been carried over to WWH via UDS Modes. Adopting WWH standards allows for more data and provides room for future expansion.
More Detailed Fault Data
Another benefit of WWH is the expansion of information contained within a fault. Currently, OBDII uses a two-byte Diagnostic Trouble Code (DTC) to indicate when a fault has occurred (e.g. P0070 indicates “Ambient Air Temperature Sensor ‘A’ Circuit Malfunction General Electrical Failure”).
Unified Diagnostic Services (UDS) expands the 2-byte DTC into a 3-byte DTC, where the third byte indicates the “failure mode.” This failure mode is similar to the Failure Mode Indicator (FMI) used in the J1939 protocol. For example, previously in OBDII, you might have the following five faults:
- P0070 Ambient Air Temperature Sensor Circuit
- P0071 Ambient Air Temperature Sensor Range/Performance
- P0072 Ambient Air Temperature Sensor Circuit Low Input
- P0073 Ambient Air Temperature Sensor Circuit High Input
- P0074 Ambient Air Temperature Sensor Circuit Intermittent
With WWH, these are all consolidated into one code P0070, with 5 different failure modes indicated in the third byte of the DTC. For example, P0071 now becomes P0070-1C.
WWH also offers more fault information, such as severity/class and status. Severity will indicate how urgently the fault needs to be reviewed, while the fault class will indicate which group the fault belongs to based on GTR specifications. Additionally, fault status will indicate if a fault is pending, confirmed, or if the test for this fault has been completed in the current driving cycle.
In summary, WWH-OBD expands upon the current OBDII framework to offer even more diagnostic information to the user.
Geotab Supports WWH-OBD
Geotab has already implemented the WWH protocol in our firmware. Geotab employs a complex protocol detection system, where we safely probe what is available on the vehicle, to figure out if OBD-II or WWH is available (in some cases, both are).
At Geotab, we are continuously improving our firmware to expand the information our customers gain. We have already started to support 3-byte DTC information and continue to add more fault information being outputted by vehicles. When new information becomes available via OBDII or WWH (such as a new PID or fault data), or if a new protocol is implemented in the vehicle, Geotab makes it a priority to quickly and accurately add it to the firmware. We then immediately send the new firmware out to our units over-the-air so our customers are always getting the most benefit from their devices.
Growth Beyond OBDII
OBDII contains 10 standard modes for getting the diagnostic information required for emissions standards. The issue is that these 10 modes have not been sufficient.
Over the years since OBDII implementation, several UDS modes have been developed to enrich the data available. Each vehicle manufacturer uses their own PIDs and implements them via additional UDS Modes. Information that was not required via OBDII data (such as odometer and seat belt usage) became available via UDS Modes.
The reality is that UDS contains more than 20 additional modes, on top of the current 10 standard modes available via OBDII, meaning UDS has more information available. But that is where WWH-OBD comes in, looking to incorporate UDS Modes with OBDII to enrich the data available for diagnostics, while still maintaining a standardized process.
Conclusion
In the growing world of IoT, the OBD port remains important for vehicle health, safety, and sustainability. While the number and variety of connected devices for vehicles increases, not all devices give and track the same information. Additionally, compatibility and security can vary from device to device.
With the multitude of OBD protocols, not all telematics solutions are designed to work with every type of vehicle currently on the road. Good telematics solutions should be able to understand and translate a comprehensive set of vehicle diagnostic codes.
