Tesla's FSD V14 Lite Update for Older Hardware 3 Vehicles Is Drawing Complaints From Owners Reporting Overheating and Autopilot Computer

The update, initially rolled out to HW3 cars in late June and broadly distributed on July 21 via software version 2026.20.6.11 (FSD v14.3.6), is a simplified version of the HW4-developed FSD v14 model. HW3 systems have only 8 GB of RAM and roughly one-eighth of HW4's memory bandwidth, which is why Tesla stuck with FSD v12.6 on these cars for over a year. Now, users report Autopilot computers reaching temperatures above 90 degrees Celsius, with some measurements hitting 96 degrees.

Service mode screenshots show error code APP_w141_ECU_Thermal_Issue, triggering a red steering wheel icon and forcing FSD to disable until the hardware cools. According to Electrek, some cases involve complete Autopilot computer failure requiring replacement. Tesla hasn't confirmed the update causes hardware failures, and the APP_w141 thermal error has been a known HW3 issue for years, often linked to cooling system problems like low coolant, air bubbles in the Octovalve, or clogged radiators. Still, the spike in reports right after the update's wider release has drawn attention to the software, with speculation that the more demanding AI model is pushing the already-strained HW3 platform further.