1. OBD Inspection
Using SAE J2534

2. Overview Drew Tech System view of the OBD Interface
Options for OBD communications
Benefits from standard interface
DrewTech’s use of SAE J2534 in BAR
Potential for other programs moving forward

3. Drew Technologies Background
Products used for OEM Engineering, Diagnostics, End of Line testing, recall programs, and OBD testing
Commercial relationship with global automakers
Key supplier for essential tools and factory diagnostics programs in USA, Europe, and Japan
Co-wrote several SAE standards including SAE J2534 and J1699
Support validation and testing of SAE and EPA standards for several OEMs

4. Vehicle Interface Device Communications
Explain diagram of SAE J2534 PC
Application
OBD Interface
Vehicle
OBD
API
OBD
API
Vehicle
Protocol
ECUs

5. OBD Interface Challenges
Each vendor’s OBD Interface communicates differently with a PC application
With every IM program, a decision must be made:
Option 1: Write your own API and comm. spec for the OBD Interface
Option 2: Use a single vendor’s proprietary API and comm. spec
This decision is very important, and will have implications throughout the entire program.

6. OBD Interface Spec Choices
Choices IM programs face
Option 1
Write a Customized OBD Comm Spec
Option 2
Single Vendor Proprietary OBD Spec
Advantages
Allows the IM program to support multiple devices from different vendors
Allows the IM program to design a system that gives them all of the data needed for future analysis
IM program can easily switch between different OBD devices and vendors
Disadvantages
No communication spec is 100% perfect at first.
A lot of effort is required for the IM program to figure out all of the details of how the com API works
The IM program will need to create a validation test to make sure every device is compliant
the level of effort is greatly reduced for the IM program because they can use what is already available
The IM program will be forced to use one vendor, and cannot easily change vendors down the road
There may be some limitations in the vendor’s device that reduces the amount of data that can be collected and analyzed.
When there is a problem, who’s fault is it? The Device vendor or IM application? More difficult to determine without a written spec and compliance test

7. Option 3: Develop with a Standard
In the service and repair world, almost all automakers globally are using a standard OBD Interface for their dealership diagnostic tools
Advantages
There are some standards that are already developed, tested, and proven
Lower cost in program development
Requiring a standard device allows more transparency among device vendors
Easier to diagnose issues in the field if hardware is built to a standardized spec
Will help OBD Interfaces become more of a commodity
The most popular global standard for vehicle interfaces is SAE J2534

8. SAE J2534 Standard SAE J2534 was created for emissions reprogramming
First version published in 2002, latest version will publish this year
Initially intended for emissions programming, but was quickly adapted into other uses
There are over 50 different software applications for diagnostics and reprogramming available today that can be supported from a J2534 interface.
There are three versions: J2534-1, J2534-2, and J The base specification is J and it contains everything needed for emissions testing

9. Legislation Requiring J2534
EPA - EPA requires OEMs to comply with SAE J2534 for pass-through reprogramming beginning with model year Reprogramming information be made available within 3 months of vehicle introduction for new models. For vehicles, EPA specifically allows OEMs to use J2534 technology on 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.
CARB - 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 J 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.
EURO V - Reprogramming of vehicle control units shall be conducted in accordance with SAE J2534.
Massachusetts Right to Repair – Requires OEM Diagnostics and all module reprogramming using SAE J2534 for Model Year 2015 and newer vehicles.

10. ETI J2534 Survey Results
n=622
N=598

11. Do you offer state-mandated OBD emissions testing for your customers?
ETI J2534 Survey Results
Do you offer state-mandated OBD emissions testing for your customers?
n=585

12. Do you offer state-mandated OBD emissions testing for your customers?
ETI J2534 Survey Results
Do you offer state-mandated OBD emissions testing for your customers?
Since you perform OBD emission testing, would you like to be able to perform the test using your J2534 device?
n=585
n=159

13. SAE J2534 API Functions

14. Drew Tech’s use of J2534 for BAR-DAD
Bar released the DAD hardware and Comm spec near the end of 2012
These specifications are proprietary and unique for California
Developing a new piece of hardware for the DAD was expected to take up to 6 months, but DrewTech wanted to begin software development immediately
Drew Tech wrote a “wrapper” to convert the BAR Comm. spec to work over SAE J2534
The J2534 wrapper allows DrewTech to prototype with any SAE J2534 device
This rapidly accelerated development for DrewTech, allowing tests with usable hardware in instantly instead of waiting several months for the production hardware

15. J2534 Testing
Screenshot of the devices we could have used with our SAE J2534 wrapper

16. Drew Tech’s use of J2534 for BAR-DAD
View of how DrewTech developed BAR DAD using SAE J2534
Proved concept that SAE J2534 is capable of emissions testing
Final product will be changed to prevent tampering PC
BAR OIS
BAR Comm.
Layer
OBD Device
Vehicle
Drew
J2534
Wrapper
SAE
J2534
Vehicle
Protocol
ECUs

17. J2534 and Tampering
SAE J2534 pushes the intelligence back into the PC application
The messages being “passed thru” are direct communications to the vehicle
It would not be beneficial for someone to insert a simulator between the J2534 devie and the PC because it would be more difficult than simulating the OBD2 end of the vehicle
Using SAE J2534 also gives the IM program more direct control of the interface and access to more timing details
Moving the intelligence to the PC allows the IM program to have more control over the “magic”. I.e. protocol determination order and handling special no-comm vehicles.

18. J2534 Conclusions
This exercise proved that SAE J2534 was capable of supporting emissions testing applications
The same wrapper could be used to allow other IM programs to support OBD devices that use SAE J2534
Because J2534 supports multiple communications methods, it becomes easy for the IM program to support USB, Ethernet, Bluetooth, wireless, and cellular devices.
Final version of DrewTech DAD software tool will have special security ensuring that only a certified DAD device will communicate.