As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LOW PRESSURE AND BLEED LIGHT. REPLACED CONTROLLER & REGULATOR ON NR1 ENG PRECAUTIONARY FOR LOW PRESSURE AND BLEED LIGHT. ACCOMPLISHED RUN-UP IAW MM, WITH BOTH BLEEDS ISOLATED, PACKS ON DUCT PRESSURES WERE NORMAL & WITHIN PLUS OR MINUS 2 PSI OF EACH OTHER. SHIFTS OCCURED NORMAL IN EACH DIRECTION.