SAE J2534, Part II: How Much Money Are You Losing By Not Doing Vehicle Reflashing?

SAE J2534, Part II: How Much Money Are You Losing By Not Doing Vehicle Reflashing?

In Part I of this series, I talked about what J2534 was and a bit about how it works. I would like to use this followup article to lower the fear factor and tell you what to expect when setting up a computer to run a J2534-supported software program.

In Part I of this series, I talked about what J2534 was and a bit about how it works. I would like to use this followup article to lower the fear factor and tell you what to expect when setting up a computer to run a J2534-supported software program. One of the industry gurus I spoke with for the last article, Mark Zachos, chair of SAE J3138 committee and president of DG Technologies, was kind enough to talk to me about some of the most common questions and concerns their support folks field with the VSI-2534 interface kit.

Mark pointed out, “Well, before we get into plugging into the car, there are several questions that service providers have. Among those, of course, is the issue of getting it all to work without damaging the car. But, one big question is: When will I make money at this?”

How do I get this to work?
There are a couple of terms you need to familiarize yourself with because, if you have not already made the leap, our job includes IT these days. (See the accompanying sidebar for a key to primary terms.) Take the word Firmware, for example. This is tricky because technically the “reflash file” you install is firmware, but, generally, when the term is used in a 2534 setup, it is talking about the software version that is on the VCI device itself. To make all of these things talk to one another, you have to match up the OE software, the PC operating system, the plug ins (Java, web browsers and a few OE specific plug ins) and the VCI firmware. Outdated or incompatible versions can put the brakes on the whole communication.

Sounds hard? It’s not. Developers and automakers say to always keep everything updated to the latest version unless a message warns you otherwise. This makes taking 15 seconds to scan the help topics or news section of the website very important. Most of the time the automaker site will have warnings posted where you have to work to miss them.

After you do any kind of change, save yourself hours of potential headaches by logging out of the OEM site and completely restarting everything in the prescribed order: PC, connect the 2534 VCI, start the software, then turn on the car, for example. Yes, the car will often need to be shut off and turned back on several times during the operation. Generally start with “on” when you are establishing communications. Experienced re-programmers call this the “key dance,” although it is becoming the push-button dance.

If you have all of the software updated and ready to go, you may still have a couple of things to check. Make sure you have internet access working — open a browser and hit a website. The next thing you must do is to make sure your particular J2534 box is selected within the automaker software. Some automaker applications, like GM’s, will lead you through it. Toyota, for example, stores your settings in its Techstream application, so you will need to go into settings and choose your VCI the first time you use it. In both cases, the automakers have an excellent graphic help guide to get you started on their website.

The first time is always the worst time. You may have to enter a license, as in the aforementioned Techstream, or you may have to install various drivers (another one of those terms) or updates to them. I figure it takes me about 30 minutes to setup a J2534 package for most automakers. It will go much better if you read all of their documentation prior to attempting it.

One of the things mentioned were licenses. When you download the application for reflashing, most of the time the actual interface software is a free download, but there is a subscription to the website to get the actual information. You are asking for trouble when you attempt to move the VCI around between multiple machines to service the same brand. Most automakers take similar approaches to their software, as companies like Microsoft or Adobe. By looking at IP addresses, if they suspect that you are sharing your subscription — by the number of different machines accessing the same account or geographical use data — they will shut down your machine and you will have some explaining to do to get it turned back on.

It seems that there are as many different approaches to reprogramming as there are automakers. You can find information on how these subscriptions work at You will also find links to all the OEM sites and information on how their programming works. Most of the European brands will take more time to configure. Up to the early 2000s, many Asian brands could not be updated by J2534 methods, or at all. Almost every manufacturer has a car line or model with some idiosyncrasy to software updates. These are generally the “collaborative” models, like the VW Routan, which was actually built by Chrysler.

I cannot stress enough how important it is to read the TSBs and procedures for the vehicle in advance of starting a repair. Very few reflash operations will result in a “bricked module” that you have to pay for should something go wrong, but the process can go from five minutes of turning the key off and on while you hit enter on the computer, to a very time-consuming process.

I may not have convinced you to begin programming, but I will ask this: If now is not the time, when will it be? There are mountains of repair procedures that cannot be completed without a flash or recode. If you wait until it is a part of every operation, the big question, “When will I make money with this?,” will be replaced with, “How much money am I losing by not doing this?”


Firmware — operational software on a piece of software. Typically, a vehicle ECU or some type of interface device, like a J2534 box.
Driver — a piece of helper software that allows a piece of software to operate a piece of hardware.
DLL — Dynamic Link Library. This is part of a driver file for our purposes and part of the Windows approach to hardware/software interaction. Mostly, if you hear about a .dll from your machine, it is because something has gone very wrong, or there is a mismatch with a new piece of hardware.
VCI — Vehicle Communications Interface. A J2534 device is a VCI that allows a software service on a computer to talk to a car with a completely different operating system.

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