Why was J2534 created?


At the turn of the century the EPA and CARB noticed that many vehicles on the road were not meeting emissions standards because of old calibrations. J2534 was their solution. Now all vehicle service facilities can update module calibrations and keep vehicles in check. As the years have gone by and J2534 has matured, some manufacturers have seen J2534 as a way to satisfy other needs such as diagnostics.


Who created J2534?


J2534 was created and is continuously modified by the SAE (Society of Automotive Engineers) to satisfy the legislation the EPA put into law. Drew Technologies has been involved with the creation of SAE J2534 from the beginning. We have also helped many OEM's with the creation and maintenance of their J2534 re-flashing software.


Who regulates J2534


From the SAE document

U.S. Environmental Protection Agency (EPA) and the California Air Resources Board (CARB) "OBD service information" regulations include requirements for reprogramming emission-related control modules in vehicles for all manufacturers by the aftermarket repair industry.


EPA requires OEMs to comply with SAE J2534 for pass-through reprogramming beginning with model year 2004. Reprogramming information be made available within 3 months of vehicle introduction for new models. For 1996-2003 vehicles, EPA specifically allows OEMs to use J2534 technology on 1996 -2003 model year vehicles as long as OEMs make all additional hardware (i.e. cables) available for sale at a fair and reasonable price to the aftermarket to allow for the reprogramming of these vehicles. OEMs must make this additional hardware available for sale independently and cannot require the purchase of their OEM specific scan tool in order to receive this additional hardware.


Beginning with the 2004 model year, reprogramming methods used for passenger cars, light-duty trucks, and medium-duty engines and vehicles shall be compatible with SAE J2534-1 Paper, “Recommended Practice for Pass-Thru Vehicle Programming, September December 2004, which is Incorporated by reference herein, for all vehicle models that can be reprogrammed by franchised dealerships or authorized service networks.


Reprogramming of vehicle control units shall be conducted in accordance with SAE-J2534.


Differences in J2534?


There are three different J2534 specifications that are currently active:

J2534-1 has been published and is incorporated into regulations. This specification details the requirements for reprogramming emissions-related controllers. It is unlikely to change.

J2534-2 is constantly evolving, and allows OEMs to add features for their own use. This specification contains information on how to implement optional features in a standard way. Future technologies could bring new requirements in both hardware and software.

J2534-3 is the compliance test for J2534-1. It makes sure that a J2534-1 device has a high probability of working with an OEM application. In the future, regulators may require that devices pass this test before they can be marketed and sold as “J2534-1 compliant” devices.