COMM
Briggs & Stratton
Communication Bus Fault
Controller displays COMM or COMMS LOSS and remote monitoring or ATS communication fails.
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Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
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Possible Causes
Broken or reversed communication cable between generator and ATS/monitor, Incorrect termination or shielding, Surge-damaged communication port, Incompatible accessory module
How to Fix / Troubleshooting
Safety first: Turn controller to OFF before connecting or disconnecting communication cables.
- Inspect cabling: Trace the low-voltage communication cable (often twisted pair) between the generator controller and ATS or remote module. Look for cuts, kinks, or water intrusion.
- Check terminations: Ensure wires are landed on the correct terminals (A/B, +/−) and polarity is not reversed.
- Remove add-ons: Temporarily disconnect non-essential accessories (Wi-Fi modules, remote displays) to see if COMM fault clears, indicating a bad accessory.
- Replace damaged components: If the cable tests good but communication is still lost, the ATS control board or generator controller communication port may be damaged and require replacement.
- Clear the code: After restoring communication, cycle controller to OFF then AUTO and verify normal status reporting.
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Repair Difficulty
Medium
3/5
Required Part
Communication Harness
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