As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT NR 280 - IAH - PHX - CREW REPORTED, FELL DIFFERENTIAL LIGHT ILLUMINATED ON TAKEOFF, FOLLOWED BY "B" FLT CONTROL LOW PRESS LIGHT. HYD QTY'S WERE INITIALLY MATCHED, OVER TIME "B" QTY WAS DROPPING WHILE "A" QTY WAS INCREASING. CREW DIVERTED TO SAN ANTONIO, TX. NO EMERGENCY WAS DECLARED. THE LANDING WAS UNEVENTFUL. MX REPLACED THE"A" SYSTEM PRESSURE MODULE. OPERATIONAL/LEAK CHECK WAS GOOD. THE A/C WAS RETURNED TO SERVICE.