As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CABIN PRESSURIZATION ELECTRONIC SYSTEM IN STANDBY, CABIN PRESSURE SURGES (OSCILLATING CABIN ALTITUDE) IN DESCENT. OUTFLOW VALVE INDICATOR IS NOT OSCILLATING. OK IN MANUAL. CABIN PRESSURE CONTROLLER FAULTY. REPLACED CPC, PERFORMED PRESSURE TEST--PASSED. NO REPEATS SINCE ORIGINAL.