Generator display shows E08 and the unit will not start in AUTO mode.

Safety first: Turn the generator OFF and isolate AC power to the built-in battery charger if it is fed from utility power.

• Measure battery voltage: Use a multimeter at the battery terminals. If below Yamaha's low-voltage threshold (often around 11.5–12.0 V), charge the battery with an external charger and retest.
• Inspect charger AC feed: Confirm that the charger is receiving AC input (check its breaker or fuse). Restore power if tripped.
• Check charger output: With AC applied, measure DC output at the charger leads. If there is no output or it is out of spec, replace the Yamaha battery charger module.
• Clean and tighten terminals: Remove corrosion from battery posts and cable ends. Tighten securely.
• Replace old battery: If the battery will not hold charge after proper charging, replace it with a Yamaha-approved starting battery of the correct CCA rating.
• Clear code and test: After restoring proper voltage, clear E08 and perform an automatic start test.