I've had a v3 OVMS module on my Nissan LEAF for almost 6 years. Wi-Fi only version. It has been a bit flaky recently; not appearing on my Wi-Fi and not creating an AP either. A day later after a power cycle due to car activity it would show up again. It now has no signs of life. I have removed the SD card (works OK on another machine) and have been trying to flash the thing with esptool as per the instructions on the OVMS wiki. I have a windows 10 PC and Raspberry Pis available. Both do show the OVMS device as a port when plugged in via USB. When doing any work with esptool there is never any response from the serial port.
Anybody got advice on what to try next?
Suggest you try to get connected as a USB serial terminal. Then while connected, press the reset button on the board and see if there is any activity on the terminal. That will at least show you if the module is reachable via USB.