The scan tool interface on today’s vehicles has been around for a long time. In 1978, manufacturers started to roll out a new on-board diagnostic system (OBD) on their vehicles equipped with electronic carburetors, electronically controlled emissions control devices, and a vehicle interface that allowed the technician to check DTCs and a few parameters with a new piece of equipment known as a ‘scan tool”. In 1988, manufactures were required to install a ‘check engine light” to alert the customer of issues with their vehicle. In addition, the manufacturers were required to monitor the operation of many vehicle systems. Several manufacturers had already implemented those features many years earlier, but this was one of the first standards to be implemented across the industry. As the years rolled by, the systems became more sophisticated, with each manufacturer deciding what and how their interface would work. From a technician’s point of view, it was more like the Wild West, as nothing was standardized.
In the USA, starting in 1994 and fully implemented by 1996, a new diagnostic system, OBD II or OBD second generation, was introduced. OBD II implementation varied based on the country, but it was fully implemented worldwide by 2013. OBD II was required for all tier 1 manufacturers and designed to standardize a lot of vehicle diagnostics across the manufacturers. This move was good for our industry as it made scan tools more accessible while standardizing many DTC numbers and features such as freeze frame and failure record information.
The addition of more components required faster data transmission speeds. In 1983 Bosch developed a new communication protocol known as CAN (Controller Area Network). Many renditions of CAN have been developed since then. North America was very slow at implementing the new communication protocols such as CAN, CAN FD, Keyword 2000, Flex Ray, Most, Ethernet, and LIN protocols, which are now used across the industry.
As the complexity of the vehicle communication system increased, it became apparent that an update to the OBD II standard was also needed. An update to the OBD II standard falls under SAE standard J1979-2, ISO standard 14229, or OBD II UDS (Unified Diagnostic Services). OBD II UDS is being introduced in many 2025 models and is designed to be fully implemented by 2027. What this change does is standardize the diagnostics protocol from all of the control modules. This means that you will have enhanced diagnostic capabilities for systems that do not have anything to do with vehicle emissions. The communication protocols have not changed, with CAN, CAN FD, LIN, Flex ray, and others still being used in vehicles.
This update simply makes changes to the communication information layers which allows more diagnostic information to be available for the technician. OBD UDS development did not start just a couple of years ago. This software’s development started in 2001 and continued with three different versions: UDS 1, UDS 2, and finally, UDS 3.
UDS UPDATES THE FOLLOWING:
- Malfunction diagnostics: DTC-based readiness, extended data records for DTCs, snapshot support for up to 5 DTCs with two freeze frames each. Freeze frames are only recorded for emissions-related DTCs, which result in an MIL, while failure records will be stored for all DTCs. Freeze frame data will not update no matter how many times the failure occurs. Failure record data will update every time the diagnostic runs and fails.
- The number of DTCs available: We are running out of 2-byte code numbers. With UDS adopting a 3-byte format, that issue has been eliminated. This change will allow DTCs to pinpoint the cause of an issue more accurately as more DTCs become available.
- List all DTCs in a readiness flag group with additional information for each DTC, including readiness, pending status, confirmed status, and completed drive cycle status.
- Controller reprograming changes
- Remote routine activation
- Controller and sensor data exchange
- Greatly improve the functionality of the generic scan tool features
At this point, you are probably wondering why you need to know about this UDS update. The answer is quite simple: your current scan tool may not operate on a vehicle equipped with UDS. I would encourage you to visit with your scan tool manufacturer now, as many companies do not have equipment compatible with UDS systems.
In addition, when you are connected to a UDS-equipped vehicle, you will find that your scan tool has a lot more data and functionality than a standard OBD II vehicle. Where the information is available in your scan tool, the menu may also change, so you will need to spend some time learning what is available and which menu you need to access to retrieve the information you desire.
Well, that is about all the time we have for now. Until next time, remember, “Some people take good care of their cars, others treat them as part of the family.”
