What was found
PRESSURIZATION SYSTEM "AUTO FAIL" LIGHT ILLUMINATED AFTER LANDING. GROUNDED - YES. (RESOLVED ON W/O: 1883346 TASKCARD: N/R-00001 ) REMOVED & REPLACED AFT OUTFLOW VALVE ASSY REF B737-900 AMM 21-31-03-400-801. PULLED & RESET 3 TOTAL C/BS. ACCOMPLISHED "MANUAL MODE" TEST PER AMM 21-31-00-710-801, GROUND FUNCTIONAL CK BOTH CABIN PRESSURE CONTROLLER & CABIN PRESSURE CONTROL SYSTEM GROUND TEST PER AMM 21-31-00-700-802, OPS CK NML. AIRCRAFT RELEASED FROM MEL 21-15C, C/N 22032462. REVERSAL OF CONFIGURATION CHANGE ACCOMPLISHED BY REMOVING 1 TOTAL C/B COLLAR & RESET SAME. SEAMC NOTIFIED "MARK.".