As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
HYDRAULIC SYSTEMS G, B & Y WILL NOT PRESSURIZE WITH APU. APU WITH BLEED ON IN BOOST MODE WITH PACKS ON OR OFF NO PRESSURIZATION. SYSTEMS PRESSURIZE NORMAL WITH NR 1 ENGINE BLEED. REPLACED RESERVOIR PRESSURIZATION UNIT IAW MM, OPERATIONS CHECKED & LEAK CHECKED GOOD.