As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AUTO FAIL ILLUMINATED DURING CLIMB, PER QRH ALT MODE SELECTED. PRESSURIZATION NORMAL. GROUNDED - YES. PERFORMED B737-900 FIM 21-31 TASK 801. CONTROLLER #1 FAULTED CODE 88 (SIGNAL TO OUT FLOW VALVE) FAIL. REPLACED OFV WITH NEW REF B737-900 AMM 21-31-03. ETOPS SIG SYSTEM: SUCCESSFUL GROUND VERIFICATION OF PRESSURIZATION SYSTEM--AUTO/ MANUAL OPERATION AMM 21-31-00-710-801 & 21-31-00-700-802.