blackhat620
You Had to be There
Evolution of Onboard Diagnostics
OBD stands for On-Board Diagnostics. In the early 1970s the U.S. adopted The Clean Air Act, which mandated that vehicle manufacturers develop more efficient, lower emission vehicles. Manufacturers soon determined that mechanical systems alone were not sufficient to achieve the emission reductions required by the new law. This led to the development of the first computer-controlled automotive OBD. A car's OBD system is comprised mainly of software designed into the vehicle's on-board computer to detect emission-control system malfunctions as they occur by monitoring virtually every component and system that can cause increases in emissions.
The first generation of OBD systems - known as "OBD I" - was introduced in 1981. Because each vehicle manufacturer developed its own system, there was no standardization among this generation of technology. As a result, manufacturer-specific OBD I systems required a variety of diagnostic software and hardware. In general, OBD I vehicles were built through model year 1995.
In search of a better solution, the Environmental Protection Agency (EPA) later established standards for improved vehicle diagnostics. The resulting standards -- known as "OBD II," "Global OBD II" or "Generic OBD II" - are part of a system the Society of Automotive Engineers (SAE) developed to regulate automotive electronic diagnosis. OBD II is required for all vehicles (imported and domestic) sold in the U.S. beginning in 1996 which dictates the use of a common diagnostic link connector and software for monitoring fuel and emission systems. Technicians are able to use the same tool to test any OBD II compliant vehicle without special adapters or manufacturer-specific tools which are necessary for OBD I vehicles. This allows one tool design to connect with any passenger vehicle sold in the U.S. after 1996.
OBD II systems are more sophisticated than OBD I - they seek out potential problems sooner and alert the driver to these issues through the "Check Engine" light or Malfunction Indicator Light (MIL). By alerting the owner of malfunctions as they occur, repairs can be sought promptly, which results in fewer emissions from the vehicle.
OBD I:
The original on-board diagnostics (OBD I) refers to most cars manufactured 1981 - 1995. Unfortunately, due to no clear set of standards for OBD I cars, there are different ways used to communicate and interface with the car's computer, which allowed for multiple interpretations amongst vehicle manufacturers.
Diagnostic Link Connectors (DLCs) allow the Code Scan Tool to communicate or "plug into" the vehicle's computer(s). Before OBD II standards, manufacturers used different data link connectors to communicate with the vehicles.
The vehicle's DLC may be found in several different places and have many different configurations depending on the make and model. Check for the necessary DLC and its location in pre-OBD II (1995 and older) domestic vehicles:
• Chrysler (1989 -1995)
• Ford and Lincoln/Mercury (1984 -1995)
• GM (1981 - 1995)
OBD II:
Beginning in 1996, all passenger cars and light trucks (8,500 lbs. GVW or less) built for sale in the U.S. were required to be OBD II-compliant. In California, the GVW limit is 14,000 lbs. GWV stands for Gross Vehicle Weight. This information usually can be found on a sticker located on the driver's doorframe.
Vehicles over 8500 lbs (14,000 lbs. California) are considered heavy duty and are exempt from the requirement to be OBD II compliant. Usually a scanner from the manufacturer or from a higher end tool company is required in order to interface with heavy-duty vehicles. Although some 1994 & 1995 vehicles are OBD II-compliant, no OBD II vehicles were manufactured before 1994.
Here are three ways to determine if your vehicle is OBD II equipped:
1. All OBD II cars and light trucks will have a 16-pin "D" shaped diagnostic connector. If your connector has fewer pins, don't worry. Manufacturers are not required to use all 16 pins and they can use them as they see fit. It should be located on the driver's side, under the dash near the steering wheel. Connector placement may vary slightly depending on the manufacturer. Please Note: Some 1994 & 1995 vehicles (most notably GM) may be equipped with the OBD II 16 pin connector but are not OBD II compliant. For these vehicles, be sure to check the VECI decal as outlined in #2 below.
2. Refer to the Vehicle Emissions Control Information Decal that is located in the engine compartment.
3. Refer to the manufacturer's certified service manual containing emissions information.
Note: Many 1996 and newer vehicles (notably heavy-duty trucks) are equipped with the 16-pin OBD II connector, but they do not link with OBD II scanners.
EOBD:
European On-Board Diagnostics (EOBD). EOBD is the European equivalent of the American OBD II standard, which applies to all gasoline cars sold in Europe beginning January 1, 2001 and all diesel & LPG cars manufactured beginning January 1, 2003.
(Note: Do not confuse EOBD with EOBD2/EOBDII, as they are not the same thing see below).
www.omitec.com/en/support/technology-briefs/brief-history-of-eobd/
CAN Bus:
CAN or Controller Area Network is a serial communication language especially suited for networking "intelligent" devices as well as sensors and actuators within a system. As vehicles transition to more sophisticated electronic systems- to reduce vehicle weight and increase fuel efficiency, on-board computers will be required to handle significantly more data. (Electronic throttle control, steering and braking systems are three common examples.) CAN provides a much faster data link between the computer and each vehicle system, much as a DSL connection provides today's consumers faster data transfer than do dial-up Internet services.
CAN (Controller Area Network) was first developed in 1983 by Robert Bosch GmbH, a German company. Robert Bosch GmbH started an internal project to develop an in-vehicle network. The CAN protocol was officially introduced in 1986 at the SAE (Society of Automotive Engineers) congress in Detroit and the first CAN controller chips from Intel and Philips Semiconductors appeared in 1987. In 1991 Bosch published the CAN 2.0 specification and in 1993 CAN was adopted by ISO (International Standards Organization) as ISO11898.
The EPA has mandated that all vehicles sold domestically be CAN-equipped beginning with the 2008 model year. It is projected that about 14% of all vehicles on the road will be CAN-equipped in 2008. Some vendors began using CAN exclusively in the model year of 2004 (Ford, Jaguar, and Mazda). While other manufacturers implemented it selectively in their vehicles beginning in the 2004 model year (Mercedes, Porsche, SAAB, and Toyota).
Additional Reading on CAN Bus:
www.omitec.com/en/support/canbus/
http://hem.bredband.net/stafni/developer/frames.htm
www.parallax.com/dl/docs/prod/comm/canTechOvew.pdf#search='how%20does%20controller%20area%20network%20work?'
DTC:
When the vehicle on-board computer recognizes and identifies a problem, a DTC or Diagnostic Trouble Code for that fault is stored in its memory. These codes are intended to help the technician to determine the root cause of a problem. OBD II Diagnostic Trouble Codes consist of a five-digit alphanumeric code. (Note: Prior to OBDII there were no standard DTC codes and the codes were manufacture specific.)
Generic OBD II Diagnostic Trouble Codes (DTC) are those codes common to all compliant vehicles, regardless of make or model for European, Asian and domestic cars. Generic DTC typically begin with ‘P0’ or ‘P2’ (‘P’ referring to Power train), followed by a 3-digit number (i.e., P0420 or P2420). These codes were originally designed to warn of faults that could cause the vehicle to emit excessive air pollution.
Enhanced OBD II (EOBD2/EOBDII) Diagnostic Trouble Codes (DTC) are those codes unique to a vehicle of a specific year, make, model (and possibly engine size). Enhanced DTC are assigned by the vehicle manufacturers to cover situations not already covered by a Generic DTC. Enhanced DTC typically begin with 'P1', followed by a 3-digit number (i.e., P1404).
OBD stands for On-Board Diagnostics. In the early 1970s the U.S. adopted The Clean Air Act, which mandated that vehicle manufacturers develop more efficient, lower emission vehicles. Manufacturers soon determined that mechanical systems alone were not sufficient to achieve the emission reductions required by the new law. This led to the development of the first computer-controlled automotive OBD. A car's OBD system is comprised mainly of software designed into the vehicle's on-board computer to detect emission-control system malfunctions as they occur by monitoring virtually every component and system that can cause increases in emissions.
The first generation of OBD systems - known as "OBD I" - was introduced in 1981. Because each vehicle manufacturer developed its own system, there was no standardization among this generation of technology. As a result, manufacturer-specific OBD I systems required a variety of diagnostic software and hardware. In general, OBD I vehicles were built through model year 1995.
In search of a better solution, the Environmental Protection Agency (EPA) later established standards for improved vehicle diagnostics. The resulting standards -- known as "OBD II," "Global OBD II" or "Generic OBD II" - are part of a system the Society of Automotive Engineers (SAE) developed to regulate automotive electronic diagnosis. OBD II is required for all vehicles (imported and domestic) sold in the U.S. beginning in 1996 which dictates the use of a common diagnostic link connector and software for monitoring fuel and emission systems. Technicians are able to use the same tool to test any OBD II compliant vehicle without special adapters or manufacturer-specific tools which are necessary for OBD I vehicles. This allows one tool design to connect with any passenger vehicle sold in the U.S. after 1996.
OBD II systems are more sophisticated than OBD I - they seek out potential problems sooner and alert the driver to these issues through the "Check Engine" light or Malfunction Indicator Light (MIL). By alerting the owner of malfunctions as they occur, repairs can be sought promptly, which results in fewer emissions from the vehicle.
OBD I:
The original on-board diagnostics (OBD I) refers to most cars manufactured 1981 - 1995. Unfortunately, due to no clear set of standards for OBD I cars, there are different ways used to communicate and interface with the car's computer, which allowed for multiple interpretations amongst vehicle manufacturers.
Diagnostic Link Connectors (DLCs) allow the Code Scan Tool to communicate or "plug into" the vehicle's computer(s). Before OBD II standards, manufacturers used different data link connectors to communicate with the vehicles.
The vehicle's DLC may be found in several different places and have many different configurations depending on the make and model. Check for the necessary DLC and its location in pre-OBD II (1995 and older) domestic vehicles:
• Chrysler (1989 -1995)
• Ford and Lincoln/Mercury (1984 -1995)
• GM (1981 - 1995)
OBD II:
Beginning in 1996, all passenger cars and light trucks (8,500 lbs. GVW or less) built for sale in the U.S. were required to be OBD II-compliant. In California, the GVW limit is 14,000 lbs. GWV stands for Gross Vehicle Weight. This information usually can be found on a sticker located on the driver's doorframe.
Vehicles over 8500 lbs (14,000 lbs. California) are considered heavy duty and are exempt from the requirement to be OBD II compliant. Usually a scanner from the manufacturer or from a higher end tool company is required in order to interface with heavy-duty vehicles. Although some 1994 & 1995 vehicles are OBD II-compliant, no OBD II vehicles were manufactured before 1994.
Here are three ways to determine if your vehicle is OBD II equipped:
1. All OBD II cars and light trucks will have a 16-pin "D" shaped diagnostic connector. If your connector has fewer pins, don't worry. Manufacturers are not required to use all 16 pins and they can use them as they see fit. It should be located on the driver's side, under the dash near the steering wheel. Connector placement may vary slightly depending on the manufacturer. Please Note: Some 1994 & 1995 vehicles (most notably GM) may be equipped with the OBD II 16 pin connector but are not OBD II compliant. For these vehicles, be sure to check the VECI decal as outlined in #2 below.
2. Refer to the Vehicle Emissions Control Information Decal that is located in the engine compartment.
3. Refer to the manufacturer's certified service manual containing emissions information.
Note: Many 1996 and newer vehicles (notably heavy-duty trucks) are equipped with the 16-pin OBD II connector, but they do not link with OBD II scanners.
EOBD:
European On-Board Diagnostics (EOBD). EOBD is the European equivalent of the American OBD II standard, which applies to all gasoline cars sold in Europe beginning January 1, 2001 and all diesel & LPG cars manufactured beginning January 1, 2003.
(Note: Do not confuse EOBD with EOBD2/EOBDII, as they are not the same thing see below).
www.omitec.com/en/support/technology-briefs/brief-history-of-eobd/
CAN Bus:
CAN or Controller Area Network is a serial communication language especially suited for networking "intelligent" devices as well as sensors and actuators within a system. As vehicles transition to more sophisticated electronic systems- to reduce vehicle weight and increase fuel efficiency, on-board computers will be required to handle significantly more data. (Electronic throttle control, steering and braking systems are three common examples.) CAN provides a much faster data link between the computer and each vehicle system, much as a DSL connection provides today's consumers faster data transfer than do dial-up Internet services.
CAN (Controller Area Network) was first developed in 1983 by Robert Bosch GmbH, a German company. Robert Bosch GmbH started an internal project to develop an in-vehicle network. The CAN protocol was officially introduced in 1986 at the SAE (Society of Automotive Engineers) congress in Detroit and the first CAN controller chips from Intel and Philips Semiconductors appeared in 1987. In 1991 Bosch published the CAN 2.0 specification and in 1993 CAN was adopted by ISO (International Standards Organization) as ISO11898.
The EPA has mandated that all vehicles sold domestically be CAN-equipped beginning with the 2008 model year. It is projected that about 14% of all vehicles on the road will be CAN-equipped in 2008. Some vendors began using CAN exclusively in the model year of 2004 (Ford, Jaguar, and Mazda). While other manufacturers implemented it selectively in their vehicles beginning in the 2004 model year (Mercedes, Porsche, SAAB, and Toyota).
Additional Reading on CAN Bus:
www.omitec.com/en/support/canbus/
http://hem.bredband.net/stafni/developer/frames.htm
www.parallax.com/dl/docs/prod/comm/canTechOvew.pdf#search='how%20does%20controller%20area%20network%20work?'
DTC:
When the vehicle on-board computer recognizes and identifies a problem, a DTC or Diagnostic Trouble Code for that fault is stored in its memory. These codes are intended to help the technician to determine the root cause of a problem. OBD II Diagnostic Trouble Codes consist of a five-digit alphanumeric code. (Note: Prior to OBDII there were no standard DTC codes and the codes were manufacture specific.)
Generic OBD II Diagnostic Trouble Codes (DTC) are those codes common to all compliant vehicles, regardless of make or model for European, Asian and domestic cars. Generic DTC typically begin with ‘P0’ or ‘P2’ (‘P’ referring to Power train), followed by a 3-digit number (i.e., P0420 or P2420). These codes were originally designed to warn of faults that could cause the vehicle to emit excessive air pollution.
Enhanced OBD II (EOBD2/EOBDII) Diagnostic Trouble Codes (DTC) are those codes unique to a vehicle of a specific year, make, model (and possibly engine size). Enhanced DTC are assigned by the vehicle manufacturers to cover situations not already covered by a Generic DTC. Enhanced DTC typically begin with 'P1', followed by a 3-digit number (i.e., P1404).
