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SMA Solar Technology Error Codes

Expert reference guide covering all SMA Sunny Boy inverter diagnostic codes with comprehensive troubleshooting procedures and professional repair guidance

Quickly identify problems with your SMA solar system and learn the correct response procedures

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SMA Inverter Models

SMA Solar Technology produces an extensive lineup of premium inverter systems for residential and commercial solar installations. The Sunny Boy series represents single-phase inverter technology with high efficiency and reliability, while Sunny Tripower models provide three-phase solutions for larger installations. These diagnostic codes are applicable to the majority of SMA inverter systems sold in the United States. Error indicators typically manifest as numeric error codes on the inverter display, LED status indicators, and status messages in the Sunny Portal monitoring system.

How to Read Error Codes

• Check inverter display for numeric error codes (e.g., 33, 39, 102, 202, 301)
• Review LED status indicators on inverter
• Check Sunny Portal for system status messages
• Note error code number and any additional information
• Consult SMA documentation for your specific model

SMA Product Series

• Sunny Boy - Single-phase high-efficiency inverters
• Sunny Tripower - Three-phase inverters for larger systems
• Sunny Central - Large-scale central inverters
• Data Logger - System monitoring and communication
• Sunny Portal - Cloud-based monitoring platform

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Understanding Diagnostic Codes

SMA inverter systems incorporate sophisticated diagnostic capabilities that automatically detect operational issues. When a problem is identified, the system communicates through numeric error codes displayed on the inverter, LED status indicators, and status messages in the Sunny Portal monitoring system. This intelligent diagnostic framework enables rapid problem identification and helps determine the appropriate response. All SMA inverter series (Sunny Boy, Sunny Tripower) utilize continuous performance monitoring with real-time error detection. Error codes are typically numeric (e.g., 33, 39, 102, 202, 301, 501, 3401, 3501, 6402, 7001) that indicate specific system conditions or faults. Some codes like 33 and 39 may appear particularly in winter months and are often non-critical. Always reference your specific model's installation manual for precise code definitions.

Grid Connection Errors

Problems with AC grid voltage, frequency, and connection.

Code	Meaning	Possible Causes	Solutions
102	Grid Fault/Grid Overvoltage Fast - Inverter detected fast overvoltage in grid	•Utility grid voltage too high •Grid voltage fluctuations •Transformer tap settings •Grid instability •Voltage regulation issue	Do not attempt to override safety shutdown Check utility grid voltage with multimeter Contact utility company to report voltage issues Wait for grid voltage to return to normal range System will automatically reconnect when voltage stabilizes Contact certified installer if voltage issues persist May require utility company intervention
202	Grid Fault/Grid Undervoltage Fast - Fast undervoltage in grid detected	•Utility grid voltage too low •Grid voltage fluctuations •Transformer issues •Grid instability •Voltage drop in distribution	Do not attempt to override safety shutdown Check utility grid voltage with multimeter Contact utility company to report voltage issues Wait for grid voltage to return to normal range System will automatically reconnect when voltage stabilizes Contact certified installer if voltage issues persist
301	Grid Fault/Voltage Increase Protection - Inverter detected unexpected voltage increase in grid	•Grid voltage increase protection activated •Voltage rise protection triggered •Grid instability •Voltage regulation issue	Check grid voltage parameters Verify grid parameters are correctly configured Wait for grid conditions to stabilize System will automatically reconnect when conditions are normal Contact installer if problem persists
501	Grid Fault/Grid Frequency Disturbance - Grid frequency deviation from allowable range detected	•Grid frequency too high •Grid frequency too low •Grid instability •Frequency fluctuations •Grid synchronization issue	Check grid frequency (should be 50Hz or 60Hz depending on region) Verify frequency is within allowable limits Inverter will automatically attempt to reconnect when frequency returns to normal Wait for grid frequency to stabilize Contact utility company if frequency is consistently out of range Contact installer if problem persists
33	Input Voltage Too High - Inverter recognizes input voltage is too high	•Too many modules per string •String voltage exceeds maximum •Cold weather voltage rise •Incorrect string configuration •Module mismatch	Check PV generator wiring configuration Review PV system design and sizing Verify number of modules per string matches inverter specifications Account for cold weather voltage rise in calculations Verify module specifications match system design Contact certified installer to verify string configuration This may occur in winter months and is often non-critical
39	Insufficient Conditions for Feed-in - Inverter not feeding in due to insufficient conditions	•Low solar irradiance •Insufficient DC voltage •Grid conditions not met •Startup conditions not fulfilled •Normal winter operation	No action required - this is often normal in winter months Inverter will automatically resume operation when conditions are optimal Check solar irradiance levels Verify DC voltage is sufficient Wait for conditions to improve This is typically non-critical and resolves automatically

DC Voltage and Isolation Errors

Problems with DC input voltage and electrical isolation.

Code	Meaning	Possible Causes	Solutions
3401	DC Overvoltage / Overvoltage Input A (SW) - Input voltage at Input A is too high	•Too many modules per string •String voltage exceeds maximum •Cold weather voltage rise •Incorrect string configuration •Module mismatch	Check DC input voltage at Input A Verify number of modules per string matches inverter specifications Review string configuration in installation manual Account for cold weather voltage rise in calculations Verify module specifications match system design Contact certified installer to verify string configuration
3501	Insulation Resistance / Isolation Fault - Isolation fault detected in DC circuit	•Damaged PV module insulation •Water ingress in junction boxes •Damaged DC wiring insulation •Ground fault in PV array •Moisture in connections	Immediately shut down the system Do not attempt to restart until fault is resolved Inspect all PV module connections and junction boxes Check DC wiring for damage or water ingress Test isolation resistance with megohmmeter Check for moisture in connections Contact certified SMA installer immediately This is a serious safety condition requiring professional diagnosis
DC Voltage Too Low	DC input voltage below minimum operating threshold	•Too few modules per string •Shading on panels •Faulty modules •DC wiring losses •String configuration error	Check string voltage with multimeter Verify minimum number of modules per string Inspect panels for shading Check for faulty modules in string Verify DC wiring connections Review string configuration Contact certified installer if voltage remains low

Temperature and Overheating Errors

Problems with inverter temperature and thermal protection.

Code	Meaning	Possible Causes	Solutions
6402	Self-Diagnosis / Overtemperature - Inverter detected internal overheating	•Insufficient ventilation •Direct sunlight on inverter •High ambient temperature •Blocked air vents •Faulty cooling fan	Improve ventilation around inverter Ensure inverter is not in direct sunlight Check that air vents are not blocked Verify adequate clearance around inverter Check cooling fan operation Allow inverter to cool down before restart Contact installer if temperature remains high after improving ventilation
7001	Fault Sensor Internal Temperature - Internal temperature sensor in inverter is defective	•Faulty temperature sensor •Sensor wiring issue •Internal sensor failure •Communication error with sensor	Check temperature sensor connections Verify sensor is functioning Contact SMA service for sensor diagnostics May require inverter service or replacement Do not attempt to repair yourself

DC Current and Power Errors

Problems with DC current and power generation.

Code	Meaning	Possible Causes	Solutions
6406	DC Overcurrent / Overcurrent Input A (HW) - Too high current at Input A detected	•Too many modules per string •Short circuit in string •Faulty modules •DC wiring issue •Current exceeds maximum	Check DC current at Input A Verify string configuration Inspect for short circuits in string Check for faulty modules Verify DC wiring connections Contact certified installer for diagnosis Do not attempt to repair yourself
No DC Power	Inverter not receiving DC power from solar panels	•DC disconnect open •String breakers off •Faulty DC connections •No solar irradiance •Panel failure	Check DC disconnect switches Verify string breakers are ON Inspect DC connections Check for solar irradiance (daytime) Verify panels are generating DC voltage Check for panel or string failures Contact installer if DC power should be available

Communication and Monitoring Errors

Problems with communication and monitoring systems.

Code	Meaning	Possible Causes	Solutions
No Communication with Data Logger	Inverter cannot communicate with SMA Data Logger	•Communication wire break •Data Logger offline •Network issue •Communication protocol error	Check communication wiring between inverter and Data Logger Verify Data Logger is powered and online Check network connection Restart Data Logger if needed Verify communication settings Contact installer if communication cannot be restored
Sunny Portal Not Accessible	Sunny Portal monitoring not accessible or showing errors	•Internet connection issue •Data Logger offline •Server connectivity problem •Account access issue	Check internet connection Verify Data Logger is online Check Sunny Portal server status Verify account credentials Restart Data Logger if needed Contact SMA support if portal remains inaccessible

Internal Inverter Errors

Problems with inverter internal systems and hardware.

Code	Meaning	Possible Causes	Solutions
Internal Inverter Error	Internal inverter fault or hardware error	•Internal inverter fault •Control board issue •Hardware failure •Component malfunction	Attempt inverter restart If error persists, contact SMA service Do not repeatedly restart if error continues Note error code and contact certified installer May require inverter replacement or repair
Power Stage Error	Inverter power stage fault	•Power stage failure •IGBT failure •DC/AC conversion issue •Hardware malfunction	Contact SMA service immediately This requires professional diagnosis Inverter may need repair or replacement Do not attempt to repair yourself

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Critical Safety Notice

Do not attempt DIY repairs on your SMA solar system. The majority of diagnostic codes relate to high-voltage DC and AC electrical systems, grid connection safety mechanisms, or critical safety features. Specific codes requiring immediate professional intervention include: 3501 (Isolation Fault), 6402 (Overtemperature), and 6406 (DC Overcurrent). Upon encountering these codes, immediately shut down the system if safe to do so and contact a certified SMA installer without delay.

Professional service is mandatory—contact a licensed solar installer or reach out to SMA technical support for expert assistance.

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Maintenance Guidelines

Scheduled Service Requirements

✓Professional inspection and service annually by certified SMA installer
✓Monthly visual inspection of solar panels for damage or soiling
✓Clean panels quarterly or as needed based on local conditions
✓Monitor system performance daily through Sunny Portal
✓Check inverter status and LED indicators monthly
✓Verify Data Logger is online and communicating

Proactive Maintenance Strategies

✓Keep panels clean to maximize energy production
✓Trim trees and vegetation to prevent shading
✓Ensure adequate ventilation around inverter
✓Monitor production trends for early problem detection
✓Keep firmware updated for latest features and fixes
✓Review system alerts and error codes promptly

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Frequently Asked Questions

What does error code 33 (Input Voltage Too High) mean?

Error code 33 indicates that the inverter recognizes the input voltage is too high. Check PV generator wiring configuration and review PV system design and sizing. Verify the number of modules per string matches inverter specifications and account for cold weather voltage rise. This may occur in winter months and is often non-critical. Contact a certified installer to verify string configuration.

What does error code 39 (Insufficient Conditions for Feed-in) mean?

Error code 39 indicates that the inverter is not feeding in due to insufficient conditions. No action is required - this is often normal in winter months. The inverter will automatically resume operation when conditions are optimal. Check solar irradiance levels and verify DC voltage is sufficient. This is typically non-critical and resolves automatically.

What should I do if I see error code 102 (Grid Overvoltage Fast)?

Error code 102 indicates that the inverter detected fast overvoltage in the grid. Do not attempt to override the safety shutdown. Check utility grid voltage with a multimeter and contact the utility company to report voltage issues. Wait for grid voltage to return to normal range. The system will automatically reconnect when voltage stabilizes. Contact a certified installer if voltage issues persist.

What does error code 3501 (Isolation Fault) mean?

Error code 3501 indicates an isolation fault detected in the DC circuit. Immediately shut down the system and do not attempt to restart until the fault is resolved. Inspect all PV module connections and junction boxes, check DC wiring for damage or water ingress, and test isolation resistance. This is a serious safety condition requiring professional diagnosis. Contact a certified SMA installer immediately.

What should I do if my inverter shows error code 6402 (Overtemperature)?

Error code 6402 indicates that the inverter detected internal overheating. Improve ventilation around the inverter, ensure it is not in direct sunlight, check that air vents are not blocked, verify adequate clearance around the inverter, and check cooling fan operation. Allow the inverter to cool down before restart. Contact an installer if temperature remains high after improving ventilation.

Can I repair my SMA system myself?

High-voltage DC and AC electrical work must exclusively be performed by licensed professionals to ensure safety compliance. Homeowners can safely perform basic tasks like cleaning panels and monitoring the Sunny Portal, but all technical repairs require certified SMA installers. Unauthorized work on electrical systems poses extreme danger and violates building codes.

How do I check if my Data Logger is working?

Check Data Logger status in the Sunny Portal. Verify the Data Logger is powered and online, check the network connection, and verify communication settings. If the Data Logger is offline, check communication wiring between the inverter and Data Logger, restart the Data Logger if needed, and contact an installer if communication cannot be restored.

How often should I clean my solar panels?

Solar panels should be cleaned quarterly or as needed based on local conditions. Panels in dusty areas or areas with heavy pollen may need more frequent cleaning. Keep panels clean to maximize energy production. Inspect panels monthly for damage or excessive soiling that may require immediate cleaning.

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Summary

Proper interpretation of diagnostic codes is essential for effective SMA solar system troubleshooting. This comprehensive reference enables quick problem identification and guides appropriate response actions. SMA systems utilize numeric error codes displayed on inverter displays, LED status indicators, and status messages in the Sunny Portal monitoring system to indicate specific sensor and system malfunctions. Sunny Boy and Sunny Tripower inverters provide diagnostic information through error codes and monitoring systems for convenient diagnosis.

⚠️Complex diagnostic situations, especially those involving high-voltage DC and AC electrical systems and grid connection safety, require immediate professional evaluation. Critical codes demanding urgent response include: 3501 (Isolation Fault), 6402 (Overtemperature), and 6406 (DC Overcurrent). These indicators represent serious safety hazards requiring certified SMA installer response. Adherence to scheduled maintenance protocols and immediate attention to diagnostic codes extends equipment service life and minimizes long-term operational costs. Note that some codes like 33 and 39 may appear particularly in winter months and are often non-critical—always consult your specific unit's installation and service manual for precise interpretations.