Dos and don’ts of reprogramming with a J2534-compliant device

July 28, 2017
G. Jerry Truglia’s taught “Reprogramming with J2534,” on July 27 during NACE Automechanika 2017 in Chicago.

CHICAGO — Did you know that, depending on who you talk to at the OEMs, anywhere from 40 percent to 70 percent of the drivability concerns you deal with are resolved by reprogramming the Engine Control Module’s software? According to some sources, the incidence of problems with other systems (drive convenience, for example) is even higher!

Besides the repetitive warning that you’ve heard from me “ad nauseum” about checking the service information system of your choice for any related Technical Service Bulletins, there isn’t much more you can do about solving this type of complaint unless you are familiar with, and equipped to perform, a “reflash” on the offending module. For most ancillary systems, that means owning the factory equivalent scan tool or paying someone who does. But for many of the OEMs, taking care of those drivability issues can be performed with a compatible J2534 “PassThru” device – a device that connects your PC or laptop to the vehicle’s Diagnostic Link Connector. Then, by going to the OEM’s service web site and downloading the appropriate software (at a fee, of course), you can perform the reflash in your own shop rather than farm it out to someone else’s.

G. Jerry Truglia instructs his course “Reprogramming with J2534” to a full room at NACE Automechanika Chicago.

But performing a reprogramming on any given manufacturer’s ECM is not without its pitfalls. For example, on some European makes, the process can take an entire day and require access to every module on the vehicle network. If you aren’t familiar with these pitfalls, you may find yourself well in the middle of a reprogramming attempt, only to be stopped in a most unpleasant manner – including the demise of the module you were trying to reprogram.

Not to worry, though, especially if you sat in on G. Jerry Truglia’s class, “Reprogramming with J2534,” on July 27 during NACE Automechanika 2017 in Chicago. Truglia is an experienced technician, shop owner, trainer and consultant with nearly 40 years practical experience under his belt. In fact, when you say someone “wrote the book” on a specific topic, with Truglia, that is a very real possibility! And it showed, as Truglia led his attendees through the maze of dos and don’ts of reprogramming with a J2534-compliant PassThru device.

Truglia started off his presentation with a quick synopsis of the experience he’s accumulated as a tech and shop owner. He let the attendees know that there is money to be made performing vehicle reprogramming for their customers and offered practical tips on how to access the preliminary information they absolutely needed to know before they even started buying the needed equipment. He cautioned his audience to first check the equipment requirements by accessing the information on the OEM service site, showing them where they could not only find the needed information but where to find the related links. He pointed out that some OEMs were not compatible with the latest Windows operating systems and how to perform a work around. Truglia also shared from his own experience serving multiple car lines that some OEM software is not compatible with others, and should be hosted on different laptops, making it clear that if a shop wanted to start offering this service, it might be best to do so one manufacturer at a time and shared his thoughts on where best to start. Truglia also pointed out that this builds experience, which builds confidence – the confidence they would need when they got to the more complicate vehicle makes.

The presentation covered specifics needed on a wide range of OEMs, and also included some hard won personal observations Truglia shared with his students. His goal, as he shared with me before the class started, was to “provide everyone with information on what they would need to know about J2534 reprogramming in order to keep them out of trouble”. One less known bit of information he shared was a good example, as he made sure that everyone attending understood how important it was to use the correct battery maintainer on the car during the programming process, pointing out that not only was it critical to maintain the proper system voltage to the module but it was also critical to avoid any AC “ripple” that may float on top of the DC voltage the maintainer was putting out. “Never use a regular battery charger”, Truglia cautioned his students, showing them the AC voltage most chargers allowed through and explaining how that alone could spell the death of the module they were trying to update.

Nearing the end of his allotted time, Truglia recapped what he had shown his guests, adding that reprogramming was not as hard as many make it out to be – but you do have to know what you’re doing before you make that first attempt. Those that left the room after Truglia’s session completed now certainly fall into that category.

About the Author

Pete Meier | Creative Director, Technical | Vehicle Repair Group

Pete Meier is the former creative director, technical, for the Vehicle Repair Group with Endeavor Business Media. He is an ASE certified Master Technician with over 35 years of practical experience as a technician and educator, covering a wide variety of makes and models. He began writing for Motor Age as a contributor in 2006 and joined the magazine full-time as technical editor in 2010. Pete grew the Motor Age YouTube channel to more than 100,000 subscribers by delivering essential training videos for technicians at all levels. 

Connect with Pete on LinkedIn.

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