SPH 3000–6000TL BL-UP / SPH 4000–10000TL3 BH-UP hybrid (Error 2xx–6xx codes)
Growatt Error 203 error code
PV array insulation resistance to earth is below the inverter's isolation threshold.
Likely causes
- Damaged or pinched DC cable insulation
- Water or moisture inside an MC4 connector or DC junction box
- Panel frame or mounting rail with an earth leakage path
- Very long or wet DC runs on a site with no insulation allowance
Checks to run, in order
- 1Check that the PV panel enclosure/frame is properly grounded, as the manual requires first
- 2Isolate the DC side and inspect DC cables and connectors for damage, water or corrosion
- 3Insulation-test each string to earth with a megger
- 4Reconnect one string at a time to identify which string trips the fault
Fixes
- Repair or replace damaged DC cable and connectors
- Dry out and reseal wet connectors, then retest insulation
- Bond panel frames and rails to earth and restart the inverter
When to escalate
If every string insulation-tests clear to earth and Error 203 returns, ask Growatt to check the inverter's insulation monitoring circuit.
Fix it with the right tools
Check the system around the fault before replacing parts: load, battery bank, PV string and commissioning settings. If you need a second opinion, send the code and your inverter model to our team.
Before you open the inverter
- Isolate both the AC and DC sides, then confirm the display is dead before touching terminals.
- Use insulated tools and one hand where possible. DC arcs do not self-extinguish like AC.
- If you see burnt terminals, swollen cells, leaking electrolyte or a burning smell, stop and escalate instead of resetting the fault.
Questions installers ask
What does Growatt Error 203 mean?
PV array insulation resistance to earth is below the inverter's isolation threshold.
How do I fix Growatt Error 203?
Repair or replace damaged DC cable and connectors Dry out and reseal wet connectors, then retest insulation Bond panel frames and rails to earth and restart the inverter
When should I escalate Growatt Error 203?
If every string insulation-tests clear to earth and Error 203 returns, ask Growatt to check the inverter's insulation monitoring circuit.
Can I reset Growatt Error 203 myself?
Only after isolating the AC and DC sides and running the checks above. If Growatt Error 203 returns immediately, stop resetting it and escalate; a repeating fault usually points to a real circuit, battery or hardware problem.
Which models show Growatt Error 203?
Growatt Error 203 is documented for SPH 3000–6000TL BL-UP / SPH 4000–10000TL3 BH-UP hybrid (Error 2xx–6xx codes). Confirm the code on your own unit's display or manual before ordering parts.
More Growatt error codes
- Growatt 01Fan is locked (displayed as F01 on the SPF ES Lite).
- Growatt 02Internal component temperature is over 100 °C (F02 on the ES Lite).
- Growatt 03Battery is over-charged / battery voltage is too high (F03 on the ES Lite).
- Growatt 04Battery voltage low.
- Growatt 05Output is short-circuited (F05 on the ES Lite).
- Growatt 06Output voltage is too high. The manual groups 06/58 as 'output abnormal' — inverter voltage above 150 Vac or below 40 Vac.
Guidance reviewed 17 October 2026 by the Mishka Energy installer team. Error codes vary by brand, model family and firmware; confirm against the manufacturer manual.
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