Generator controller shows E05 and prevents start, or shuts down shortly after start with no AC output.

Safety first: Turn OFF the generator, open the output breaker, and lock out/tag out the system. Verify no backfeed from utility.

• Visual inspection: Remove the alternator access cover. Inspect the AVR module and wiring for burn marks, melted insulation, or loose terminals.
• Check main stator connections: Tighten all terminal lugs at the alternator output and at the generator terminal block using an insulated wrench. Look for discoloration indicating overheating.
• Measure output: With a qualified person and proper PPE, start the generator and measure line-to-line voltage at the alternator terminals. If voltage is very low or zero, the AVR or excitation circuit may have failed.
• Inspect sensing leads: Verify the small gauge sensing wires from the alternator to the AVR and Kubota controller are intact and firmly connected. Repair any damaged wires.
• Replace AVR if needed: If the AVR shows visible damage or no change in output when adjusted (if adjustable), replace it with the correct Kubota-specified AVR model.
• Re-test: After repairs, run the generator, verify correct voltage and frequency, then re-energize loads.