As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FOLLOW-UP TO HISTORY OF PRESSURIZATION PANEL (P5-6) NOT DIMMING ISSUES. GROUNDED - YES. ENGINEERING REQUEST - REMOVED/REPLACED CABIN PRESSURE CONTROL MODULE REF B737-900 AMM 21-31-02. ALL REQUIRED TESTS PER SAME MM OPS NML. GROUND VERIFICATION TESTS GOOD REF SAME AMM. BOTH CPC'S SHOWED ON POWER UP - SYSTEM OK, NO EXISTING FAULTS AND NO INFLT FAULTS LOGGED.