1. Has EG4 identified a known hardware failure involving the 6000XP MPPT board or its internal communication circuitry?
   There is no known widespread or common failure issue with the 6000XP. In most cases where a unit experiences an internal failure, replacement may be necessary. However, every situation is different, and proper troubleshooting is needed to determine the cause and the appropriate resolution.
   
   
2. Can Fault 17 return even after a successful firmware update?
   Yes, if the firmware update does not resolve the underlying issue, the problem may occur again.
   
   
3. Does the MPPT firmware require PV power during installation? My original update was performed with PV disconnected.
   PV is not required for the inverter to be installed or operate. However, PV power is needed during certain firmware updates, as part of the update involves the MPPTs, which require power. That said, the absence of PV during an update would not necessarily cause a Fault 17 or other issues with the inverter.
   
   
4. Is approximately 12V displayed on disconnected PV inputs normal, or could it indicate an internal MPPT problem?
   It should not be reading any voltage. This could be contributing to the issue, but further troubleshooting would be needed to determine the cause.
   
   
5. Has anyone experienced these exact symptoms and successfully resolved them?
   I have seen cases where a firmware update has resolved this issue for customers. However, it is not a guaranteed fix, as the cause may vary from one situation to another.
   
   
6. Given the recurring Fault 17 and previous popping noises, would EG4 recommend replacing the inverter rather than attempting further firmware updates?
   This will depend on what we find during the troubleshooting process. We would need to complete the necessary troubleshooting steps before determining whether a replacement is needed. I recommend giving our Tech Support team a call so we can look into the issue and work toward getting it resolved as quickly as possible.

There have been no alarms and no events in the event log when I experience the problem.

I'm looking for assistance from EG4 technical support and other EG4 6000XP owners who may have experienced similar problems.

I have three EG4 6000XP inverters operating in parallel. My middle inverter has been experiencing recurring Fault 17 (Internal Communication Fault 2), along with complete loss of PV production.

Symptoms:

• Fault 17 appears intermittently, sometimes remaining active.
• Both MPPT inputs stop producing solar power.
• PV production drops to 0W, even when the other two inverters are generating normally.
• The inverter previously made abnormal popping sounds associated with the PV side.
• With PV disconnected, the inverter sometimes displays approximately 12V on PV1 and PV2.
• Fault 17 eventually disappears when the inverter enters standby, but the underlying problem remains unresolved.

Firmware history:

Signature Solar remotely updated the affected inverter on September 30, 2026. The other two inverters received firmware updates on October 2. All three currently report firmware version ccaa-1E1515.

Unfortunately, on October 9, Fault 17 returned on the same middle inverter, and it was producing absolutely no solar power.

I have currently isolated its PV input, GRID input, and AC output as a precaution. The inverter remains battery-powered for monitoring.

Similar case found on this forum:

EG4-6000XP – MPPT1 ghost voltage + both MPPTs get stuck after clouds

This customer's symptoms appear remarkably similar to mine, including Fault 17, unexpected PV voltage readings, and MPPT production failures. I noticed that EG4 Eric suggested the inverter might require replacement. The thread does not confirm the final repair or replacement outcome.

My questions:

1. Has EG4 identified a known hardware failure involving the 6000XP MPPT board or its internal communication circuitry?
2. Can Fault 17 return even after a successful firmware update?
3. Does the MPPT firmware require PV power during installation? My original update was performed with PV disconnected.
4. Is approximately 12V displayed on disconnected PV inputs normal, or could it indicate an internal MPPT problem?
5. Has anyone experienced these exact symptoms and successfully resolved them?
6. Given the recurring Fault 17 and previous popping noises, would EG4 recommend replacing the inverter rather than attempting further firmware updates?

I have photographs, screenshots, and previous technical-support correspondence available.

I would particularly appreciate assistance from @eg4eric or another EG4 technical-support representative.

Thank you!

Supporting photos and app screenshots:

The app screenshots below were captured after isolation of the affected inverter; the LCD photo shows its later standby condition.

LCD in standby: 12V PV reading and warning 26; this is not a photo of Fault 17.

PV disconnect switch.

Affected middle inverter app screenshot: standby, 0W PV and firmware ccaa-1E1515.

Other inverter: 3874W PV and the same firmware.

Other inverter: 3038W PV and the same firmware.