Tesla FSD V14.3.6 Overheats HW3 Autopilot Computers; Up to 4 Million Vehicles May Need Replacement
Tesla's July 21 release of FSD V14.3.6 (V14 Lite) to HW3 vehicles has been followed by a sharp rise in Autopilot computer overheating complaints, including hardware failures. Owners detected ECU fault codes above 90°C, with some readings reaching 96°C, forcing FSD to shut down until the computer cooled. The HW3 unit's 8GB memory and roughly one-eighth HW4 bandwidth make it vulnerable under the distilled V14 workload. Tesla has acknowledged HW3 cannot support unsupervised driving, leaving it potentially on the hook to replace computers or compensate owners of about 4 million vehicles.
On July 21, Tesla pushed FSD V14.3.6 (V14 Lite) to its HW3 fleet. Soon afterward, a large number of owners reported high-temperature warnings from the Autopilot computer, and some vehicles suffered hardware damage. Complaints surged within two weeks. In service mode, multiple owners found ECU motherboard fault codes; the alarm is triggered when motherboard temperature exceeds 90°C, and some owners measured temperatures as high as 96°C. While driving, the high temperature forced FSD to disengage and displayed a red-hand warning, putting the system into an "autonomous driving unavailable" state until the computer cooled down.
The root cause lies in the hardware generation gap. The HW3 computer has only 8GB of memory and roughly one-eighth of the bandwidth of HW4. To run the heavier V14 model on constrained hardware, Tesla introduced a distilled, streamlined version, but the high load still overwhelms the older computers. Tesla has previously acknowledged that HW3 hardware cannot deliver the "unsupervised autonomous driving" it promised, creating a potential legal obligation to replace computers or compensate owners for about 4 million vehicles.
High-temperature failures are not a new problem. They are usually associated with aging hardware, such as insufficient coolant, air bubbles in coolant lines, or blocked radiators, and predate the V14 Lite release. However, the concentrated outbreak of similar failures after this update coincides closely with its timing.
Tesla has not publicly confirmed that the software update directly causes hardware damage, nor has it disclosed whether it is monitoring ECU temperature data from the V14 Lite fleet.