DIAGNOSIS Error 5-8 indicates a communication fault between the main PCB and the display/control panel.
FIX Perform a hard reset. Unplug the machine from the wall outlet. Wait for 60 seconds. While unplugged, press and hold the power button on the machine for 20 seconds to discharge any residual power. Plug the machine back in and press the power button to restart.
IF THAT DIDN'T WORK The error persists. This requires a deeper reset. With the machine unplugged, remove the main HEPA/carbon filter. Wait 30 seconds. Reinstall the filter, ensuring it clicks into the correct position. Plug the machine back in. The error should clear if it was a sensor glitch.
HEADS UP If Error 5-8 returns after these steps, it indicates a likely hardware failure. Continued use is not advised. You must contact Dyson Support directly. Have your machine's serial number ready. The unit may require a PCB replacement.