Various angles and details of a "MaxScan OE509" – a fairly typical onboard diagnostics (OBD) handheld scanner from the first decade of the 21st century. Used to connect to the SAE J1962 Data Link Connector (DLC) found in many cars of the era.

On-board diagnostics (OBD) is a term referring to a vehicle's self-diagnostic and reporting capability. In the United States, this self-diagnostic is a requirement to comply with federal emissions standards[1] to detect failures that may increase the vehicle tailpipe emissions to more than 150% of the standard to which it was originally certified.[2]

A primary benefit of this is that OBD systems give the vehicle owner or repair technician access to the status of the various vehicle sub-systems. The amount of diagnostic information available via OBD has varied widely since its introduction in the early 1980s versions of onboard vehicle computers. Early versions of OBD would simply illuminate a malfunction indicator light (MIL) or "idiot light" if a problem was detected, but would not provide any information as to the nature of the problem. Modern OBD implementations use a standardized digital communications port to provide real-time data in addition to a standardized series of diagnostic trouble codes, or DTCs, which allow a person to rapidly identify and remedy malfunctions within the vehicle.


This section is in list format but may read better as prose. You can help by converting this section, if appropriate. Editing help is available. (September 2021)

Standard interfaces


Main article: ALDL

GM's ALDL (Assembly Line Diagnostic Link) is sometimes referred to as a predecessor to, or a manufacturer's proprietary version of, an OBD-I diagnostic starting in 1981. This interface was made in different varieties and changed with power train control modules (aka PCM, ECM, ECU). Different versions had slight differences in pin-outs and baud rates. Earlier versions used a 160 baud rate, while later versions went up to 8192 baud and used bi-directional communications to the PCM.[15][16]


The regulatory intent of OBD-I was to encourage auto manufacturers to design reliable emission control systems that remain effective for the vehicle's "useful life".[17] The hope was that by forcing annual emissions testing for California starting in 1988, [18] and denying registration to vehicles that did not pass, drivers would tend to purchase vehicles that would more reliably pass the test. OBD-I was largely unsuccessful, as the means of reporting emissions-specific diagnostic information was not standardized. Technical difficulties with obtaining standardized and reliable emissions information from all vehicles led to an inability to implement the annual testing program effectively.[19]

The Diagnostic Trouble Codes (DTC's) of OBD-I vehicles can usually be found without an expensive scan tool. Each manufacturer used their own Diagnostic Link Connector (DLC), DLC location, DTC definitions, and procedure to read the DTC's from the vehicle. DTC's from OBD-I cars are often read through the blinking patterns of the 'Check Engine Light' (CEL) or 'Service Engine Soon' (SES) light. By connecting certain pins of the diagnostic connector, the 'Check Engine' light will blink out a two-digit number that corresponds to a specific error condition. The DTC's of some OBD-I cars are interpreted in different ways, however. Cadillac petrol fuel-injected vehicles are equipped with actual onboard diagnostics, providing trouble codes, actuator tests and sensor data through the new digital Electronic Climate Control display.

Holding down 'Off' and 'Warmer' for several seconds activates the diagnostic mode without the need for an external scan tool. Some Honda engine computers are equipped with LEDs that light up in a specific pattern to indicate the DTC. General Motors, some 1989–1995 Ford vehicles (DCL), and some 1989–1995 Toyota/Lexus vehicles have a live sensor data stream available; however, many other OBD-I equipped vehicles do not. OBD-I vehicles have fewer DTC's available than OBD-II equipped vehicles.


OBD 1.5 refers to a partial implementation of OBD-II which General Motors used on some vehicles in 1994, 1995, & 1996. (GM did not use the term OBD 1.5 in the documentation for these vehicles — they simply have an OBD and an OBD-II section in the service manual.)

For example, the 1994–1995 model year Corvettes have one post-catalyst oxygen sensor (although they have two catalytic converters), and have a subset of the OBD-II codes implemented.[20]

This hybrid system was present on GM B-body cars (the Chevrolet Caprice, Impala, and Buick Roadmaster) for 1994–1995model years, H-body cars for 1994–1995, W-body cars (Buick Regal, Chevrolet Lumina (for 1995 only), Chevrolet Monte Carlo (1995 only), Pontiac Grand Prix, Oldsmobile Cutlass Supreme) for 1994–1995, L-body (Chevrolet Beretta/Corsica) for 1994–1995, Y-body (Chevrolet Corvette) for 1994–1995, on the F-body (Chevrolet Camaro and Pontiac Firebird) for 1995 and on the J-Body (Chevrolet Cavalier and Pontiac Sunfire) and N-Body (Buick Skylark, Oldsmobile Achieva, Pontiac Grand Am) for 1995 and 1996 and also for North American delivered 1994–1995 Saab vehicles with the naturally aspirated 2.3.

The pinout for the ALDL connection on these cars is as follows:

1 2 3 4 5 6 7 8
9 10 11 12 13 14 15 16

For ALDL connections, pin 9 is the data stream, pins 4 and 5 are ground, and pin 16 is the battery voltage.

An OBD 1.5 compatible scan tool is required to read codes generated by OBD 1.5.

Additional vehicle-specific diagnostic and control circuits are also available on this connector. For instance, on the Corvette there are interfaces for the Class 2 serial data stream from the PCM, the CCM diagnostic terminal, the radio data stream, the airbag system, the selective ride control system, the low tire pressure warning system, and the passive keyless entry system.[21]

An OBD 1.5 has also been used in the Ford Scorpio since 95.[22]


OBD-II is an improvement over OBD-I in both capability and standardization. The OBD-II standard specifies the type of diagnostic connector and its pinout, the electrical signalling protocols available, and the messaging format. It also provides a candidate list of vehicle parameters to monitor along with how to encode the data for each. There is a pin in the connector that provides power for the scan tool from the vehicle battery, which eliminates the need to connect a scan tool to a power source separately. However, some technicians might still connect the scan tool to an auxiliary power source to protect data in the unusual event that a vehicle experiences a loss of electrical power due to a malfunction. Finally, the OBD-II standard provides an extensible list of DTCs. As a result of this standardization, a single device can query the on-board computer(s) in any vehicle. This OBD-II came in two models OBD-IIA and OBD-IIB. OBD-II standardization was prompted by emissions requirements, and though only emission-related codes and data are required to be transmitted through it, most manufacturers have made the OBD-II Data Link Connector the only one in the vehicle through which all systems are diagnosed and programmed. OBD-II Diagnostic Trouble Codes are 4-digit, preceded by a letter: P for powertrain (engine and transmission), B for body, C for chassis, and U for network.

OBD-II diagnostic connector

Female OBD-II connector on a car
Female OBD-II type A connector pinout – front view
Female OBD-II type B connector pinout – front view. Wire placement is identical to type A, but the center groove is split in two.

The OBD-II specification provides for a standardized hardware interface — the female 16-pin (2x8) J1962 connector, where type A is used for 12-volt vehicles and type B for 24-volt vehicles. Unlike the OBD-I connector, which was sometimes found under the bonnet of the vehicle, the OBD-II connector is required to be within 2 feet (0.61 m) of the steering wheel (unless an exemption is applied for by the manufacturer, in which case it is still somewhere within reach of the driver).

SAE J1962 defines the pinout of the connector as:

1 Manufacturer discretion

GM: J2411 GMLAN/SWC/Single-Wire CAN.
Audi: Switched +12 to tell a scan tool whether the ignition is on.
VW: Switched +12 to tell a scan tool whether the ignition is on.
Mercedes[23] (K-Line): Ignition control (EZS), air-conditioner (KLA), PTS, safety systems (Airbag, SRS, AB) and some other.

9 Manufacturer discretion

GM: 8192 baud ALDL where fitted.
BMW: RPM signal.
Toyota: RPM signal.
Mercedes (K-Line): ABS, ASR, ESP, ETS, BAS diagnostic.

2 Bus positive Line

SAE J1850 PWM and VPW

10 Bus negative Line

SAE J1850 PWM only (not SAE 1850 VPW)

3 Manufacturer discretion

Ethernet TX+ (Diagnostics over IP)
Ford DCL(+) Argentina, Brazil (pre OBD-II) 1997–2000, USA, Europe, etc.
Chrysler CCD Bus(+)
Mercedes (TNA): TD engine rotation speed.

11 Manufacturer discretion

Ethernet TX- (Diagnostics over IP)
Ford DCL(-) Argentina, Brazil (pre OBD-II) 1997–2000, USA, Europe, etc.
Chrysler CCD Bus(-)
Mercedes (K-Line): Gearbox and other transmission components (EGS, ETC, FTC).

4 Chassis ground 12 Manufacturer discretion

Ethernet RX+ (Diagnostics over IP)
Mercedes (K-Line): All activity module (AAM), Radio (RD), ICS (and more)

5 Signal ground 13 Manufacturer discretion

Ethernet RX- (Diagnostics over IP)
Ford: FEPS – Programming PCM voltage
Mercedes (K-Line): AB diagnostic – safety systems.

6 CAN high

(ISO 15765-4 and SAE J2284)

14 CAN low

(ISO 15765-4 and SAE J2284)

7 K-line

(ISO 9141-2 and ISO 14230-4)

15 L-line

(ISO 9141-2 and ISO 14230-4)

8 Manufacturer discretion

Activate Ethernet (Diagnostics over IP)
Many BMWs: A second K-line for non OBD-II (Body/Chassis/Infotainment) systems.
Mercedes: Ignition

16 Battery voltage

(+12 Volt for type A connector)
(+24 Volt for type B connector)

The assignment of unspecified pins is left to the vehicle manufacturer's discretion.[24]


The European on-board diagnostics (EOBD) regulations are the European equivalent of OBD-II, and apply to all passenger cars of category M1 (with no more than 8 passenger seats and a Gross Vehicle Weight rating of 2,500 kg, 5,500 lb or less) first registered within EU member states since January 1, 2001 for petrol-engined cars and since January 1, 2004 for diesel engined cars.[25]

For newly introduced models, the regulation dates applied a year earlier – January 1, 2000 for petrol and January 1, 2003, for diesel.
For passenger cars with a Gross Vehicle Weight rating of greater than 2500 kg and for light commercial vehicles, the regulation dates applied from January 1, 2002, for petrol models, and January 1, 2007, for diesel models.

The technical implementation of EOBD is essentially the same as OBD-II, with the same SAE J1962 diagnostic link connector and signal protocols being used.

With Euro V and Euro VI emission standards, EOBD emission thresholds are lower than previous Euro III and IV.

EOBD fault codes

Each of the EOBD fault codes consists of five characters: a letter, followed by four numbers.[26] The letter refers to the system being interrogated e.g. Pxxxx would refer to the powertrain system. The next character would be a 0 if complies to the EOBD standard. So it should look like P0xxx.

The next character would refer to the sub system.

The following two characters would refer to the individual fault within each subsystem.[27]


The term "EOBD2" is marketing speak used by some vehicle manufacturers to refer to manufacturer-specific features that are not actually part of the OBD or EOBD standard. In this case "E" stands for Enhanced.


JOBD is a version of OBD-II for vehicles sold in Japan.

ADR 79/01 & 79/02 (Australian OBD standard)

The ADR 79/01 (Vehicle Standard (Australian Design Rule 79/01 – Emission Control for Light Vehicles) 2005) standard is the Australian equivalent of OBD-II. It applies to all vehicles of category M1 and N1 with a Gross Vehicle Weight rating of 3,500 kg (7,700 lb) or less, registered from new within Australia and produced since January 1, 2006 for petrol-engined cars and since January 1, 2007 for diesel-engined cars.[28]

For newly introduced models, the regulation dates applied a year earlier – January 1, 2005 for petrol and January 1, 2006, for diesel. The ADR 79/01 standard was supplemented by the ADR 79/02 standard which imposed tighter emissions restrictions, applicable to all vehicles of class M1 and N1 with a Gross Vehicle Weight rating of 3500 kg or less, from July 1, 2008, for new models, July 1, 2010, for all models.[29]

The technical implementation of this standard is essentially the same as OBD-II, with the same SAE J1962 diagnostic link connector and signal protocols being used.


In North America, EMD and EMD+ are on-board diagnostic systems that were used on vehicles with a gross vehicle weight rating of 14,000 lb (6,400 kg) or more between the 2007 and 2012 model years if those vehicles did not already implement OBD-II. EMD was used on California emissions vehicles between model years 2007 and 2009 that did not already have OBD-II. EMD was required to monitor fuel delivery, exhaust gas recirculation, the diesel particulate filter (on diesel engines), and emissions-related powertrain control module inputs and outputs for circuit continuity, data rationality, and output functionality. EMD+ was used on model year 2010-2012 California and Federal petrol-engined vehicles with a gross vehicle weight rating of over 14,000 lb (6,400 kg), it added the ability to monitor nitrogen oxide catalyst performance. EMD and EMD+ are similar to OBD-I in logic but use the same SAE J1962 data connector and CAN bus as OBD-II systems.[8]

OBD-II signal protocols

Five signaling protocols are permitted with the OBD-II interface. Most vehicles implement only one of the protocols. It is often possible to deduce the protocol used based on which pins are present on the J1962 connector:[30]

All OBD-II pinouts use the same connector, but different pins are used with the exception of pin 4 (battery ground) and pin 16 (battery positive).

OBD-II diagnostic data available

OBD-II provides access to data from the engine control unit (ECU) and offers a valuable source of information when troubleshooting problems inside a vehicle. The SAE J1979 standard defines a method for requesting various diagnostic data and a list of standard parameters that might be available from the ECU. The various available parameters are addressed by "parameter identification numbers" or PIDs which are defined in J1979. For a list of basic PIDs, their definitions, and the formula to convert raw OBD-II output to meaningful diagnostic units, see OBD-II PIDs. Manufacturers are not required to implement all PIDs listed in J1979 and they are allowed to include proprietary PIDs that are not listed. The PID request and data retrieval system gives access to real time performance data as well as flagged DTCs. For a list of generic OBD-II DTCs suggested by the SAE, see Table of OBD-II Codes. Individual manufacturers often enhance the OBD-II code set with additional proprietary DTCs.

Mode of operation/OBD services

Here is a basic introduction to the OBD communication protocol according to ISO 15031. In SAE J1979 these "modes" were renamed to "services", starting in 2003.


Various tools are available that plug into the OBD connector to access OBD functions. These range from simple generic consumer level tools to highly sophisticated OEM dealership tools to vehicle telematic devices.

Hand-held scan tools

Multi-brand vehicle diagnostics system handheld Autoboss V-30 with adapters for connectors of several vehicle manufacturers.[35]

A range of rugged hand-held scan tools is available.

Mobile device-based tools and analysis

Mobile device applications allow mobile devices such as cell phones and tablets to display and manipulate the OBD-II data accessed via USB adaptor cables or Bluetooth adapters plugged into the car's OBD II connector. Newer devices on the market are equipped with GPS sensors and the ability to transmit vehicle location and diagnostics data over a cellular network. Modern OBD-II devices can therefore nowadays be used to for example locate vehicles, monitor driving behavior in addition to reading Diagnostics Trouble Codes (DTC). Even more advanced devices allow users to reset engine DTC codes, effectively turning off engine lights in the dashboard; however, resetting the codes does not address the underlying issues and can in worst-case scenarios even lead to engine breakage where the source issue is serious and left unattended for long periods.[36][37]

OBD-II Software

An OBD-II software package when installed in a computer (Windows, Mac, or Linux) can help diagnose the onboard system, read and erase DTCs, turn off MIL, show real-time data, and measure vehicle fuel economy.[38]

To use OBD-II software, one needs to have an OBD-II adapter (commonly using Bluetooth, Wi-Fi or USB)[39] plugged in the OBD-II port to enable the vehicle to connect with the computer where the software is installed.[40]

PC-based scan tools and analysis platforms

Typical simple USB KKL Diagnostic Interface without protocol logic for signal level adjustment.

A PC-based OBD analysis tool that converts the OBD-II signals to serial data (USB or serial port) standard to PCs or Macs. The software then decodes the received data to a visual display. Many popular interfaces are based on the ELM327 or STN[41] OBD Interpreter ICs, both of which read all five generic OBD-II protocols. Some adapters now use the J2534 API allowing them to access OBD-II Protocols for both cars and trucks.

In addition to the functions of a hand-held scan tool, the PC-based tools generally offer:

The extent that a PC tool may access manufacturer or vehicle-specific ECU diagnostics varies between software products[42] as it does between hand-held scanners.

Data loggers

TEXA OBD log. Small data logger with the possibility to read out the data later on PC via USB.

Data loggers are designed to capture vehicle data while the vehicle is in normal operation, for later analysis.

Data logging uses include:

Analysis of vehicle black box data may be performed periodically, automatically transmitted wirelessly to a third party or retrieved for forensic analysis after an event such as an accident, traffic infringement or mechanical fault.

Emission testing

In the United States, many states now use OBD-II testing instead of tailpipe testing in OBD-II compliant vehicles (1996 and newer). Since OBD-II stores trouble codes for emissions equipment, the testing computer can query the vehicle's onboard computer and verify there are no emission related trouble codes and that the vehicle is in compliance with emission standards for the model year it was manufactured.

In the Netherlands, 2006 and later vehicles get a yearly EOBD emission check.[46]

Driver's supplementary vehicle instrumentation

Driver's supplementary vehicle instrumentation is instrumentation installed in a vehicle in addition to that provided by the vehicle manufacturer and intended for display to the driver during normal operation. This is opposed to scanners used primarily for active fault diagnosis, tuning, or hidden data logging.

Auto enthusiasts have traditionally installed additional gauges such as manifold vacuum, battery current etc. The OBD standard interface has enabled a new generation of enthusiast instrumentation accessing the full range of vehicle data used for diagnostics, and derived data such as instantaneous fuel economy.

Instrumentation may take the form of dedicated trip computers,[47] carputer or interfaces to PDAs,[48] smartphones, or a Garmin navigation unit.

As a carputer is essentially a PC, the same software could be loaded as for PC-based scan tools and vice versa, so the distinction is only in the reason for use of the software.

These enthusiast systems may also include some functionality similar to the other scan tools.

Vehicle telematics

OBD II information is commonly used by vehicle telematics devices that perform fleet tracking, monitor fuel efficiency, prevent unsafe driving, as well as for remote diagnostics and by Pay-As-You-Drive insurance.

Although originally not intended for the above purposes, commonly supported OBD II data such as vehicle speed, RPM, and fuel level allow GPS-based fleet tracking devices to monitor vehicle idling times, speeding, and over-revving. By monitoring OBD II DTCs a company can know immediately if one of its vehicles has an engine problem and by interpreting the code the nature of the problem. It can be used to detect reckless driving in real time based on the sensor data provided through the OBD port.[49] This detection is done by adding a complex events processor (CEP) to the backend and on the client's interface. OBD II is also monitored to block mobile phones when driving and to record trip data for insurance purposes.[50]

OBD-II diagnostic trouble codes

OBD-II diagnostic trouble codes (DTCs)[51][52] are five characters long, with the first letter indicating a category, and the remaining four being a hexadecimal number.[53]

The first character, representing category can only be one of the following four letters, given here with their associated meanings. (This restriction in number is due to how only two bits of memory are used to indicate the category when DTCs are stored and transmitted).[53]

  1. ^ Whilst this is commonly referred to as the network category, it may originally have been the 'undefined' category, hence the use of the letter 'U' rather than 'N'.

The second character is a number in the range of 0–3. (This restriction is again due to memory storage limitations).[53]

The third character may denote a particular vehicle system that the fault relates to.[51]

Finally the fourth and fifth characters define the exact problem detected.

Standards documents

SAE standards documents on OBD-II

SAE standards documents on HD (Heavy Duty) OBD

ISO standards

Security issues

Researchers at the University of Washington and University of California examined the security around OBD and found that they were able to gain control over many vehicle components via the interface. Furthermore, they were able to upload new firmware into the engine control units. Their conclusion is that vehicle embedded systems are not designed with security in mind.[54][55][56]

There have been reports of thieves using specialist OBD reprogramming devices to enable them to steal cars without the use of a key.[57] The primary causes of this vulnerability lie in the tendency for vehicle manufacturers to extend the bus for purposes other than those for which it was designed, and the lack of authentication and authorization in the OBD specifications, which instead rely largely on security through obscurity.[58]

See also


  1. ^ "Regulations for Emissions from Vehicles and Engines". US Environmental Protection Agency. Retrieved June 2, 2024.
  2. ^ CarTechBooks. "OBD-I & OBD-II: A Complete Guide to Diagnosis, Repair & Emissions Compliance". CarTechBooks. Retrieved September 15, 2023.
  3. ^ Digital Electronic Fuel Injection 16007.02-1. GM Product Service Training. August 1979.
  4. ^ "GM Today Vol 6 No 8 September 1980". General Motors. September 1980. ((cite magazine)): Cite magazine requires |magazine= (help)
  5. ^ Cox, Ronald W. (November 1985). "Local Area Network Technology Applied to Automotive Electronic Communications". IEEE Transactions on Industrial Electronics. IE-32 (4): 327–333. doi:10.1109/TIE.1985.350105. S2CID 19426686.
  6. ^ "STE/ICE Design Guide for Vehicle Diagnostic Connector Assemblies" (PDF). US: Department of the Army. August 1, 1982. Archived (PDF) from the original on August 6, 2020. Retrieved May 16, 2020.
  7. ^ "On-Board Diagnostic II (OBD II) Systems - Fact Sheet / FAQs". US: California Air Resources Board. September 28, 2009. Archived from the original on June 27, 2013.
  8. ^ a b c d e f g Ford Powertrain Control and Emissions Diagnostic Manual for Gasoline Engines. Ford Motor Company. June 9, 2011.((cite book)): CS1 maint: date and year (link)
  9. ^ "Relating to measures to be taken against air pollution by emissions from motor vehicles and amending Council Directive 70/220/EEC". The European Parliament and of the Council. October 13, 1998. Directive 98/69/EC. Retrieved May 17, 2020.
  10. ^ "OBDII Compatibility". US: PLX. Retrieved December 25, 2019.
  11. ^ "ISO 15765-4:2005 — Road vehicles — Diagnostics on Controller Area Networks (CAN) — Part 4: Requirements for emissions-related systems". International Organization for Standardization. January 2005.
  12. ^ "CAN Bus Explained – A Simple Intro (2021)". CSS Electronics. Retrieved November 22, 2021.
  13. ^ "GB 18352.6-2016 – PDF BOOK Auto-delivery". Retrieved November 22, 2021.
  14. ^ "China's stage 6 emission standard for new light-duty vehicles (final rule)" (PDF). International Council on Clean Transportation.
  15. ^ "ALDL Bluetooth AdapterUser's Guide". 1320 Electronics LLC. Retrieved November 22, 2021 – via ManualsLib.
  16. ^ "Reading GM's 160 baud ALDL Data Stream with a Standard PC Serial Port".
  17. ^ OBD-I to OBD-II: A History of On-Board Diagnostics, US: The Morey Corporation, December 21, 2022, retrieved March 23, 2023
  18. ^ "OBD - On-Board Diagnostic Program". US: California Air Resources Board. Retrieved June 2, 2024.
  19. ^ "On-Board Diagnostic II (OBD II) Systems Fact Sheet". US: California Air Resources Board. September 19, 2019. Retrieved June 2, 2024.
  20. ^ 1994 Corvette Service Manual, Book 2. General Motors Corporation. December 1993. pp. 6E3–A-166 : 6E3–A-223.
  21. ^ 1994 Corvette Service Manual, Book 2. General Motors Corporation. December 1993. pp. 6E3–A–11.
  22. ^ "EEC IV Code Reader: For 2.9L 12 Valve & Early Tdi". Ford Scorpio. UK. January 14, 2006. Retrieved June 2, 2024.
  23. ^ "Mercedes PinOut". September 30, 2019. Retrieved December 27, 2022.
  24. ^ "OBD II diagnostic interface pinout". December 2, 2017. Retrieved June 28, 2022.
  25. ^ "Directive 98/69/EC of the European Parliament". Publications Office of the European Parliament.
  26. ^ "Blog | Indramat USA". Retrieved October 27, 2023.
  27. ^ "OBD-II Check Engine Light Trouble Codes".
  28. ^ "Vehicle Standard (Australian Design Rule 79/01 – Emission Control for Light Vehicles) 2005". Australian Government ComLaw.
  29. ^ "Vehicle Standard (Australian Design Rule 79/02 – Emission Control for Light Vehicles) 2005". Australian Government ComLaw.
  30. ^ "Diagnosing Serial Data Buses". August 25, 2016.
  31. ^ "ISO 9141-2:1994". ISO. Retrieved February 19, 2020.
  32. ^ Mahajan, Gauri; Parchandekar, S.K.; Tahir, Mohammad (July 2017). "Implementation and Validation of K Line (ISO 9141) Protocol for Diagnostic Application" (PDF). International Research Journal of Engineering and Technology. 4 (7). Retrieved August 15, 2020.
  33. ^ Miller, Tim (June 7, 2019). "How Can I Read OBD2 Freeze Frame Data?". OBD Planet. Retrieved July 22, 2020.
  34. ^ Miller, Tim (February 28, 2018). "How To Read OBD2 Freeze Frame Data". OBD Advisor. Retrieved November 23, 2021.
  35. ^ "Autoboss 30 Diagnostic Coverage List" (PDF).
  36. ^ "Intro to OBD-II vehicle diagnostics and GPS tracking". OBD By Tramigo.
  37. ^ "Driving Behaviour Identification based on OBD Speed and GPS Data Analysis". Researchgate.
  38. ^ "OBD Software – Elm Electronics". Retrieved November 22, 2021.
  39. ^ "How to choose an OBD II adapter: Wi-Fi or Bluetooth – inCarDoc". CarDoctorPortal. Retrieved November 22, 2021.
  40. ^ Miller, Tim (October 31, 2021). "How Does OBD2 Software Work?". OBD Advisor.
  41. ^ "OBD Interpreter ICs". OBD Solutions. Retrieved June 2, 2024.
  42. ^ Miller, Tim (February 12, 2019). "OBD2 Diagnostic Software for Laptop/PC". OBD Advisor.
  43. ^ "OBD2 Data Logger – Easily Record & Visualize Your Car Data". CSS Electronics. Retrieved November 22, 2021.
  44. ^ "Home • IOSiX". IOSiX. Retrieved November 22, 2021.
  45. ^ "Advantages And Disadvantages Of A Dash Cam | Moneyshake Blog". Retrieved November 22, 2021.
  46. ^ "Periodic motor vehicle test (APK)". Retrieved November 22, 2021.
  47. ^ OBDuino open source OBD trip computer
  48. ^ "Advantages and Disadvantages of Personal digital assistant". GeeksforGeeks. December 15, 2020. Retrieved November 22, 2021.
  49. ^ Shashika, Muramudalige (August 24, 2015). "Cloud-based driver monitoring and vehicle diagnostic with OBD2 telematics" (PDF). IEEE International Conference on Electro/Information Technology – via
  50. ^ "What is Vehicle Telematics? Definition and FAQs | OmniSci". Retrieved November 22, 2021.
  51. ^ a b Miller, Tim (October 25, 2021). "OBD2 Codes Guides and List for Free Download". OBD Advisor.
  52. ^ Richard, David (June 4, 2021). "Complete OBD2 Codes List With Basic Explanation". Weekly Tools.
  53. ^ a b c ELM327DSL.pdf, p. 36.
  54. ^ Bright, Peter (May 15, 2010). "Car hacks could turn commutes into a scene from Speed". Ars Technica. Retrieved August 23, 2012.
  55. ^ Mastakar, Gaurav (April 6, 2012). "Experimental Security Analysis of a Modern Automobile". University of Washington and University of California San Diego. Archived from the original on September 20, 2012. Retrieved August 23, 2012.
  56. ^ Marks, Paul (July 17, 2013). "$25 gadget lets hackers seize control of a car". New Scientist. Retrieved November 5, 2013.
  57. ^ Riggers (July 2, 2012). "Video: Key fob reprogrammers steal BMW in 3 mins". PistonHeads. Retrieved July 9, 2020.
  58. ^ Van den Brink, Rob (July 10, 2012). "Dude, Your Car is Pwnd" (PDF). SANS Institute. Archived from the original (PDF) on February 23, 2013.
  • Birnbaum, Ralph and Truglia, Jerry. Getting to Know OBD II. New York, 2000. ISBN 0-9706711-0-5.
  • SAE International. On-Board Diagnostics for Light and Medium Duty Vehicles Standards Manual. Pennsylvania, 2003. ISBN 0-7680-1145-0.