What was found
(CAN) CPC AUTO MODE CONTROL UNRELIABLE IN CLIMB. DURING CLIMB, CABIN RATE OF CLIMB INDICATED [0], CABIN ALT [0FT]. NO FAULT LIGHT ILLUMINATED. MANUAL OPS OK HOWEVER UNRELIABLE IN AUTO MODE. AIR TURN BACK PERFORMED. CPC FAULT ERASED, [CPC CONT FAIL] & [CPC OFV DATA FAIL] STORED. CPC, CPCP, CIM & OFV REPLACED. AFTER CPC REPLACEMENT, ALL FAIL MSG CLEARED. WIRING CHCK SATIS. A/C RTS. (TC# 20190513021)