As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CLIMBING THROUGH 3500 FT. THE AIRPLANE STOPPED PRESSURIZING, LEVELED OFF AT 7000 & DIVERTED TO SFO. FLT 2589 INSPECTED OVB EXHAUST SOV, APPEARS THAT VALVE OPENED ON ITS OWN. DEACTIVATED EXHAUST SOV IAW AMM. DEACTIVATED INBD SOV IAW AMM. PERFORMED OPERATIONS CHECKED OF SERVICE DOOR LATCH IAW AMM. PERFORMED PRESSURIZATION CHECK IAW AMM. SECURED OVERBOARD SOV & INBD SOV WITH SAFETY WIRE.