Tuesday, October 17, 2006

OBD2 Basics

On-Board Diagnostics, in an automotive context, is a generic term referring to hardware diagnostic capability that is present in most cars and light trucks on the road today.

During the 1970s and early 1980s manufacturers started using electronic means to control engine functions and diagnose engine problems. This was primarily to meet EPA emission standards. Through the years on-board diagnostic systems have become more sophisticated.


OBD2 is a standard interface to the on-board computer of a vehicle, introduced in the mid-1990s. The California Air Resources Board (CARB) mandated that the specification be adopted for all cars sold in the United States by the year 1996 in order to simplify the implementation of an emissions testing program. An OBD-II interface allows for the readout of DTCs (Diagnostic Trouble Codes) that have been generated by the on-board computer, as well as realtime data from the sensors connected to the on-board computer. In addition, the OBD-II interface provides a means to clear the DTC list once maintenance has been completed. For a list of generic OBD-II DTCs, see Table of OBD-II Codes. Individual manufactures have been known to enhance the OBD-II code set with a host of proprietary DTCs. The OBD-II specification provides for a standarized hardware interface—the female 16-pin (2×8) J1692 assembly. Unlike the OBD-I connector, which was found under the hood of the vehicle, the OBD-II connector is located on the driver’s side of the passenger compartment near the center console. Unfortunately, the OBD-II specification does not require a particular communication protocol be used on this interface. In general, only a few of the contacts on the J1692 are populated and the configuration of populated contacts can reveal the communication protocol used by the on-board computer. There are at least five protocols in use with the OBD-II interface:

* SAE J1850 PWM (41.6 kbaud, standard of the Ford Motor Company)
o pin 2 Data high
o pin 10 Data low

* SAE J1850 VPW (Variable pulse width) (10.4 kbaud, standard of General Motors)
o pin 2 Data

* ISO 9141 (RS-232 at non-standard voltages, used by numerous manufactures including most non-American cars)
o pin 7 Data K
o pin 15 Data L (this line optional in protocol, pin may not be populated in connector)

* ISO 14230 KWP2000 (Keyword Protocol 2000)
o pin 7 Data K
o pin 15 Data L (this line optional in protocol, pin may not be populated in connector)

* ISO 15765 CAN
o pin 6 Data high
o pin 14 Data low

Note that pins 5 (battery ground) and 16 (battery positive) are present in all configurations. Also, ISO 9141 and ISO 14230 use the same pinout, thus you cannot distinguish between the two simply by examining the connector. EOBD and JOBD

In Europe the EOBD (European On-Board Diagnostics) system was mandated by European Directive 98/69/EC for all petrol vehicles made from 1 January 2001. It is similar to the American OBD-II standard. In Japan, the JOBD system is used. CAN bus

Some newer cars (usually post-2003) also support the CAN bus, a local area network in some cars that also gives access to additional hardware like radios, navigation systems, and more. By 2008, all vehicles sold in the US must come equipped with CAN bus. CAN bus devices are usually connected to via the OBD2 connector.

www.carplugs.com obdii

Sunday, April 09, 2006

How do I know what standard my car uses?

All cars and light trucks built for sale in the United States after 1996 are required to be OBD-II compliant. The European Union OBD legislation is somewhat more complicated.

An OBD-II compliant vehicle can use any of the five communication protocols: J1850 PWM, J1850 VPW, ISO9141-2, ISO14230-4 (also known as Keyword Protocol 2000), and more recently, ISO15765-4/SAE J2480 (a "flavor" of CAN). US car manufacturers were not allowed to use CAN until model year 2003, and as of this writing (June 2005) ScanTool.net, LLC is working on a CAN-compatible interface.

There are two types of diagnostic link connectors (DLCs) defined by SAE J1962 - Type A and Type B, shown in Figures 2 and 3, respectively. The main difference between the two connectors is in the shape of the alignment tab.

Location - According to J1962, Type A DLC "shall be located in the passenger or driver's compartment in the area bounded by the driver's end of the instrument panel to 300 mm (~1 ft) beyond the vehicle centerline, attached to the instrument panel and easy to access from the driver's seat. The preferred location is between the steering column and the vehicle centerline."

Fig. 1 - J1962 Vehicle Connector, Type A
(courtesy of SAE)

Type B DLC "shall be located in the passenger or driver's compartment in the area bounded by the driver's end of the instrument panel, including the outer side, and an imagined line 750 mm (~2.5 ft) beyond the vehicle centerline. It shall be attached to the instrument panel and easy to access from the driver's seat or from the Co-drivers seat or from the outside. The vehicle connector shall be mounted to facilitate mating and unmating."

Fig. 2 - J1962 Vehicle Connector, Type B
(courtesy of SAE)

As a general rule, you can determine which protocol your vehicle is using by looking at the pinout of the DLC:

Fig. 3

The following table explains how to determine the protocol:

Pin 2 Pin 6 Pin 7 Pin 10 Pin 14 Pin 15 Standard
must have - - must have - - J1850 PWM
must have - - - - - J1850 VPW
- - must have - - may have* ISO9141/14230
- must have - - must have - ISO15765 (CAN)

*Pin 15 (also called the "L-line") is optional in newer vehicles that use the ISO9141-2 or ISO14230-4 protocols.

In addition to pins 2, 7, 10, and 15, the connector should have pins 4 (Chassis Ground), 5 (Signal Ground), and 16 (Battery Positive). This means that:

PWM The connector must have pins 2, 4, 5, 10, and 16
VPW The connector must have pins 2, 4, 5, and 16, but not 10.
ISO The connector must have pins 4, 5, 7, and 16. Pin 15 may or may not be present.
CAN The connector must have pins 4, 5, 6, 14, and 16.

For your convenience, we've also compiled a list of confirmed OBD-II compliant vehicles and their respective OBD protocols, compiled from reports of our existing customers.

And lastly, you may find this page helpful:

OBDII Generic Communication Protocols by Manufacturer

Monday, March 06, 2006

New Products, Scan tool, OBD2 Cables, OBD2 Connectors

Looking for ElmScan 5 Automotive Diagnostics Scan Tool. Look at: carplugs.com

Do you need a OBD2 Cable, look at: carplugs.com

You would like to purchase premium OBD2 Connectors, look at : carplugs.com

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Saturday, January 28, 2006


In general, the federally-mandated On Board Diagnostics 2 (OBD2) platform has been a real pain in the ass. Required on all cars from model year 1996 on, the advanced computer and sensor system makes it a lot more difficult to add aftermarket modifications to your car—the go-fast kind, not the ruin-my-aerodynamics kind.
There is a single upside to OBD2, though, and that’s the requirement that all cars have an easily-accessible diagnostics port in the passenger compartment of the car. The ScanGauge is a 3-in-1 automotive computer that plugs right in, giving you tons of handy information like fuel economy, temperature, and manifold pressure, as well as trip data like maximum and average speed. But probably worth the $130 purchase price alone is the ability to read and reset vehicle ‘Trouble Codes,’ allowing you to make your own judgments about whether or not you need to take your ride in to see a professional. And if everything looks good to you (or you fix it yourself), you can use the ScanGuage to reset the Check Engine lights yourself. (Thanks, Allan!)

Monday, January 16, 2006

New Website



Carplugs.com has a new website. New lower prices on OBD2 Connector or J1962 Connector.
OBD2 Connectors is their products.

Check it out: www.carplugs.com

Thursday, January 05, 2006


Obd2 news from www.carplugs.com home of the J1962 Connector

Christoph Hammerschmidt

EETimes Germany (08/13/2004 11:00 AM EDT)
MUNICH, Germany — Microsoft Corp.'s latest foray into auto electronics has generated a dual response in the industry. While car makers tend to eye the newcomer — and industry outsider — with distrust, analysts said the software giant's telematics platform could make inroads in the market.
But the race is far from over.
By its own account, Microsoft is pursuing a volume strategy with its telematics platform introduced last week. Working with partners Italian partners Fiat and Magneti Marelli, the company plans to provide telematic services for compact cars that were previously reserved more for high-end vehicles.
Luxury car makers such as BMW and Audi therefore view Microsoft's foray with suspicion. A BMW spokesman played down the issue, saying it wasn't worth commenting on. In any case, the Munich-based auto manufacturer still considers its telematics services a unique selling point. BMW's strategy is a top-down one in which new services are introduced first in the luxury class, then gradually rolled out to economy models.
Another BMW executive also appeared to be unaffected by the Microsoft-Fiat strategy. "We don't see any reason to react to announcements," he said.
Volkswagen and Audi spokesman also declined to comment on Microsoft's telematics strategy.
IT service provider Gedas AG was less defensive. The VW subsidiary develops IT solutions for the auto industry. Dimitros Horozidis, product manager for fleet management products, predicted Microsoft will be successful with its products and with motor vehicle manufacturers.
Still, the complexity of the solutions demanded cannot be underestimated. "With commercial vehicles, particular customers insist on considerable individuality for their solutions," Horozidis said.
The Microsoft platform does have interfaces to the controller area network, or CAN-Bus, and can therefore access internal vehicle data. But implementation of the standard is not the end of it, Horozidis said. "Many manufacturers, primarily in the market for commercial vehicles, are intent on preparing customized information exclusively for their customers. In doing so, their solutions frequently exceed the CAN standard. A promising platform must therefore be freely programmable, so that service providers can use and implement additional messages on the bus."
Market researchers Ovum IT said Microsoft could make a significant dent in the auto telematics market "After all, you see Windows everywhere these days. The automotive market was an obvious candidate," said Dario Betti, a senior analyst at Ovum.
In contrast to other manufacturers, who have had only a fleeting interest in Microsoft's advances, partner Fiat committed itself to installing the platform. "It is probably true that Fiat's position in the automotive market is rather weak at the moment, but at the same time the company is one of the most active and successful players in the European telematics landscape," Betti said.
Betti cited the fact that Fiat's telematics service, "Targa Sys," is already profitable and is used by other automakers. That is one clear indicator of the service's success.
The other side of the coin, according to Ovum analysts, is that Microsoft's first generation of products are frequently sub-par. "Just think about Microsoft's first smart phones and set-top boxes," said Betti. The worst thing that could happen to Microsoft after its high-profile entry into the telematics market would be flawed first-generation products.
"Competition in this sector is brutal. Successful providers in the car-entertainment market, such as Pioneer, are already in the process of successfully claiming this market for themselves. The race is not over yet," Betti said.
—Christoph Hammerschmidt is editor-in-chief of EET.de.

Tuesday, January 03, 2006


It may come as a surprise that Microsoft has been heavily involved in car navigation systems for some time now. Until now, Microsoft has been trying to sell software for expensive navigation systems. Its new ploy is to produce an in-car computer called TBox, running on a dedicated software system called Windows Automotive.
The TBox can provide directions, make hands-free phone calls and play digital music on customers’ mobile phones, iPods or similar devices. It also allows access to telematics services such as remote vehicle diagnostics and electronic yellow pages, which the customer would purchase separately from a service provider.
Fiat Auto has already agreed to fit TBox to all 23 of its Fiat, Lancia and Alfa Romeo models. Consultancy firm Forrester Research in Massachusetts, commented that Microsoft “has finally cracked the code with a working device that provides more functionality at a lower cost than anything else available today”.
The TBox is expected to go on sale for a couple of hundred euros when its launched. A date has not been confirmed.

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