What was found
DURING CLIMBOUT THE AUTO PRESS LIGHT ILLUMINATED DUE TO HIGH CABIN RATE OF CLIMB. GROUNDED - YES. AIR TURNBACK -- REVERSED CONFIGURATION CHANGE, NO FAULTS NOTED ON #1 & #2CPC. DUE TO #1 CPC ON MEL REMOVED AND REPLACED #2 CPC, OPS CHECK GOOD IAW B737-800 AMM 21-31-01, REAPPLIED CONFIGURATION CHANGE NR 1 CPC MEL 21-14C 61612 PER TECH SERVICES #1 CPC REQUIRES REPLACEMENT. REPLACED CPC#1 REF AMM 21-31-01, CPC#2 SHOWED CABIN PRESSURE CONTROL FAULT. REPLACED CABIN PRESSURE CONTROL PANEL REF AMM 21-31-02 RESET CP #1 C/B BOTH CPC OPS TEST PASS. MANUAL MODE SYSTEM ALSO PASSES REF AMM 21-31-00.