For Shark WANDVAC WS642, “Left LED flashes: communication fault” is a distinct manufacturer-documented diagnostic intent. This page preserves the exact code or light pattern, groups every applicable catalog model and limits action to the official safe user check. Shark's official material anchors this branch with the exact wording “Left LED is flashing: Communication.”. That wording identifies the documented condition; it does not by itself prove that a battery, motor, board, sensor, dock or other replaceable component has failed. Keep “Left LED flashes: communication fault” separate from every other alert on the same appliance. Match the full number, colour, flash order, spoken phrase or display text before acting; a different pattern owns a different diagnosis and may have a different stop condition. Switch off, undock and detach only the normal hand-vac, wand and nozzle connections. Dry-clean their exposed contacts without metal tools, reconnect each part until seated and test once; a returning left-LED pattern needs Shark service. If the exact “Left LED flashes: communication fault” condition clears and the appliance completes one normal start, charge or cleaning cycle, stop the test and monitor it. If it returns unchanged, do not repeat resets or infer a part: record the code, model and serial number for authorised Shark support. Switch the vacuum off and disconnect its charger or mains plug before removing an accessible tool, bin, filter or brush. Keep battery contacts dry and never open the motor body, charger or battery pack.
Models covered
Safety first
- Switch the vacuum off and disconnect its charger or mains plug before removing an accessible tool, bin, filter or brush. Keep battery contacts dry and never open the motor body, charger or battery pack.
What the symptom may indicate
Checks in the right order
- Confirm the exact code or pattern
For Shark WANDVAC WS642, “Left LED flashes: communication fault” is a distinct manufacturer-documented diagnostic intent. This page preserves the exact code or light pattern, groups every applicable catalog model and limits action to the official safe user check.
- Make the appliance safe
Switch the vacuum off and disconnect its charger or mains plug before removing an accessible tool, bin, filter or brush. Keep battery contacts dry and never open the motor body, charger or battery pack.
- Perform the official user check
Switch off, undock and detach only the normal hand-vac, wand and nozzle connections. Dry-clean their exposed contacts without metal tools, reconnect each part until seated and test once; a returning left-LED pattern needs Shark service.
- Retest once and decide
If the exact “Left LED flashes: communication fault” condition clears and the appliance completes one normal start, charge or cleaning cycle, stop the test and monitor it. If it returns unchanged, do not repeat resets or infer a part: record the code, model and serial number for authorised Shark support.
Stop and get qualified help when
- Stop immediately for a swollen or unusually hot battery, burning or electrical smell, smoke, liquid ingress, a damaged plug or lead, sparking, harsh motor noise, or the same fault after the single safe check. Contact authorised service. If the exact “Left LED flashes: communication fault” condition clears and the appliance completes one normal start, charge or cleaning cycle, stop the test and monitor it. If it returns unchanged, do not repeat resets or infer a part: record the code, model and serial number for authorised Shark support.
Next step
Repair, replace a part, or arrange a diagnosis?
Use the checks and stop conditions above to choose a cautious next step. A symptom alone never proves that the appliance has failed.
Resolve it without buying anything
Complete the 4 user-accessible checks in order. If normal operation returns and no warning sign remains, no replacement is indicated.
Replace only the confirmed part
If the checks isolate a worn or blocked component, match its complete reference to the exact appliance model before ordering.
This guide does not identify a replacement part. Do not order a generic component from the symptom alone.
Arrange a diagnosis before replacing the appliance
Stop at any warning sign listed above. A qualified diagnosis should confirm that repair is unsafe, unavailable or uneconomical before an appliance replacement is considered.
Sources used
- Shark — Shark's official WS640/WS642 troubleshooting for Shark WANDVAC WS642 states exactly: “Left LED is flashing: Communication.” This short quotation is the source anchor for this intent.
Last checked: 30 August 2026