J2534 reprogramming brings new opportunity for business

Time was, you fiddled and tinkered, then adjusted just so to get a car to perform properly. Back then, this art form built the reputation of many mechanics and the evolution of the technician. Then, in the 1980s, GM gave us our first taste of changing a vehicle’s powertrain programming, through PROM (Programmable Read Only Memory) replacements. How high-tech it seemed, at least at the time.

As technology marched on, it brought about a new frontier in changing a vehicle’s programming, and it’s based on a standard from the Society of Automotive Engineers. Known as J2534, the standard provides a gateway to imparting new logic into automotive control systems when their “thinking” is fundamentally flawed.

WHAT IS J2534?

The standard encompasses a “recommended practice for pass-thru vehicle programming.” Essentially, as the automakers moved towards reprogrammable control units, it created the in-service need to actually provide the reprogramming function. J2534 steps outside the boundaries of being manufacturer-specific, and ties into the original generic design goals of OBD II systems. With that said, both the EPA and the California Air Resources Board required all vehicle manufacturers to meet J2534 requirements, beginning with the 2004 model year.

With the technology in place on vehicles, it opened the window of opportunity for aftermarket tool providers to build suitable reprogramming equipment.

It’s important to note that the J2534 standard does not specify hardware types or arrangements for compliant equipment. These details are left to the manufacturers of the equipment to establish designs they think are best. However, reprogramming software from any vehicle manufacturer must be compatible with hardware supplied by any tool manufacturer.

A couple of variations to the original J2534 standard have evolved since the original. J2534-1 deals exclusively with reprogramming emissions-based control modules on 2004 and newer vehicles. J2534-2 evolved as a variant for reprogramming some vehicles prior to 2004, and for some controllers not related to emissions control.


The J2534 reprogramming equipment you should consider must be able to handle the specific types of vehicles and systems that you intend to service, both now and as far as you can forecast into the future.

The bottom line is, J2534 reprogramming is here now and you simply can’t repair today’s vehicles without its capabilities. If a vehicle is running a flawed program, you must reprogram to fix it the right way.


Because of some of the open aspects of J2534-compliant design, and the types of vehicles you may need to service, all equipment is not created equally. So, a little homework is in order to seek the best match for your needs.

The best place to start is at the website of the National Automotive Service Task Force (www.nastf.org). NASTF is a cooperative effort among the automotive service industry, the equipment and tool industry and automotive manufacturers to ensure that automotive service professionals have the information, training and tools needed to properly diagnose and repair today's high-tech vehicles.

Once on the site, click on “Tools Matrix” and then on the link next to “Reprogramming Status Summary.” You will then see a matrix of vehicle manufacturers with a column titled, “J2534 software and calibrations available.” This will show you where each specific vehicle manufacturer stands regarding its ability to reprogram with J2534.

To learn more about exact details for each manufacturer, go back and click on the “Tools Matrix” link. Then, click on the links in the table on the center of the page to see the specific reprogramming details for that vehicle line. Also note the link to the “Service Information Matrix Page,” which will take you to a page with reprogramming information.

Finally, go to the “OEM Service Websites” section and choose the links of the manufacturers you’re interested in. Although each of these sites has its own unique navigation, you’ll need to “drill down” until you find specific validation information for J2534 pass-thru equipment. This specifies, by brand name, equipment validated by that manufacturer as being able to perform reprogramming on its vehicles.

Key details of each listing include the DLL and firmware version, and validations can only be assured with those specifics. Why does this matter? The J2534 equipment you’re considering for reprogramming may be validated among various vehicle lines that you plan to service, but there may be differing DLL and firmware versions. Don’t overlook this important detail in your quest for J2534 coverage.


Reprogramming is not a “poke and hope” service. That is, you don’t reprogram everything that comes your way. To learn whether a vehicle may need reprogramming or not, start with a review of Technical Service Bulletins to see if there are updates for that vehicle and its related symptoms.

The actual software used for reprogramming modules comes from the vehicle manufacturer. Most often, you can access the programming information via the web for a fee. Some manufacturers also use CD formats for distribution of reprogramming code. Fees and formats vary, so refer once again to the NASTF website as the starting place to learn more about getting reprogramming updates.


Clearly, you want to buy the best J2534 reprogramming equipment for your specific needs, but what exactly is best? Like most things, it all depends.

Once you’ve researched the equipment from the validation side of OEM service websites, talk to the reps of that specific tool company to learn more about updates and forward-compatibility. Use care to separate help from hype and stay objective with your decision.

To see how technicians feel about their J2534 equipment applications, visit the Tool and Equipment forum of the International Automotive Technicians Network at www.iatn.net. You’ll quickly get real-world insight into what works well on specific vehicles, and things to look out for.

J2534 reprogramming is here to stay and represents a new window of opportunity for servicing today’s vehicles. You no longer have to send this service to the dealer, creating a win-win scenario for your customers and your shop.