As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TAXI OUT,LE SLAT ASYM CAUTION MSG AND LIGHT ON AFTER START CHECKLIST. SEEMS TO HAPPEN WHEN SELECTING APU OFF WHILE FLAPS ARE IN TRANSIT.A/C RETURNED TO THE GATE AND MTX GROUNDED A/C MTX T/S LE SLAT ASYM MSG PER B767 FIM 27-81 FT 809 FOUND MAIN BATTERY INOP REMOVED & REPLACED MAIN BATTERY CHARGER IAW B767 AMM 24-31-02 OPS CHECK GOOD. CYCLED SLATS ON APU & ENG POWER PER B767 AMM 27-81-00. NO FAULTS NOTED. AND RETURNED A/C TO SERVICE.