As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DTW - INFLIGHT ORD-LGA. CREW REPORTED RIGHT PACK UNABLE TO MAINTAIN PRESSURE WITH LEFT PACK ON PLACARD. EMERGENCY DECLARED FLIGHT DIVERTED DTW LANDED WITHOUT INCIDENT. AIRCRAFT REMOVED FROM SERVICE. REPLACED RIGHT WATER SEPARATOR TEMPATURE CONTROL VALVE. SYSTEM GROUND CHECK NORMAL OPERATION.