Encountering unexpected performance issues while driving can be frustrating, especially when your car feels like it’s losing power despite flooring the accelerator. One user on a car enthusiast forum, Bricky, shared an intriguing experience with their Veloster, noting a significant lack of torque in 4th gear, almost as if the torque was limited to just 100ft-lb, according to their perception and potentially backed by OBD2 data. This raises important questions about how modern cars manage torque and how OBD2 scanners can help diagnose such issues.
Bricky described a scenario where, upon aggressively accelerating on the highway, their Veloster downshifted to 4th gear but delivered “ZERO torque,” barely gaining speed. The sensation was that of extreme torque limitation, which they subjectively estimated to be around 100ft-lb. Interestingly, when the transmission shifted to 5th gear, the full power seemed to return with an “aggressive shift.” This experience led Bricky to suspect that the Transmission Control Unit (TCU) might be limiting torque in 4th gear, precisely when it was needed most. To investigate this further, Bricky recorded data using an OBD2 scanner, capturing screenshots of what appears to be TCU data, seeking help in interpreting these readings.
OBD2 scanner data showing Torque Reduction Request and Actual values, indicating potential TCU torque limiting.
This situation isn’t unique to Velosters. Another forum member chimed in, sharing a similar experience with a 2018 Hyundai Kona 1.6T AWD. They described experiencing comparable shifting issues and torque delivery problems across different tuning stages. This Kona owner found relief through a Technical Service Bulletin (TSB) that provided a revised OEM TCU software update aimed at addressing “jittering clutch engagement.” While the stated purpose was clutch engagement, the update effectively “polished” the shifting algorithm, resulting in a significantly improved driving experience. The new OEM TCU tune transformed the Kona’s transmission behavior, making it responsive and perform as expected, even tightening up clutch slip.
OBD2 scanner readings comparing old and new TCU software settings for torque management.
Comparing OBD2 data from before and after the TCU update, the Kona owner highlighted a subtle but potentially crucial change: a “5 ft lbs reduction” in torque reduction settings in the new OEM TCU file. This seemingly minor adjustment showcases the intricate control modern TCUs have over engine and transmission parameters, including torque management. The experience underscores how software calibrations within the TCU can dramatically impact vehicle performance and driving feel.
For Veloster and Kona owners, and potentially drivers of other modern vehicles experiencing similar performance dips, understanding OBD2 data related to torque and TCU operation is crucial for diagnostics. While 100ft Obd2 might represent a perceived or actual torque reading in a specific scenario, it highlights the complexity of modern automotive systems. OBD2 scanners provide valuable insights into these systems, allowing users and technicians to monitor parameters like “Torque Reduction Request” and “Torque Reduction Actual,” as seen in Bricky’s data. Deciphering this data can be the first step in understanding whether a perceived performance issue is due to intentional torque limiting by the TCU, or if it indicates a mechanical problem requiring further investigation. Exploring TCU tuning options or seeking OEM software updates, as in the Kona owner’s case, can sometimes offer solutions to improve vehicle performance and address unwanted torque limitations.
