An E8-class code on the ESA II control indicates a safety / sensor-circuit fault — typically a monitored safety sensor (presence or threshold) that is not reporting correctly, miswired, or out of alignment. Check each safety sensor for power, correct wiring to the control, and proper detection-field aim. Clean the sensor lenses, confirm no reflective surfaces or moving objects sit in the field, and re-test. After correcting the sensor condition, cycle power and re-run the learn cycle to clear the latched code.