What was found
DURING PRELIGHT, FOUND "AUTO FAIL" AND "ALTN" LIGHTS ILLUMINATED ON PRESSURIZATION PANEL W/ MODE SELECTOR SWITCH TO AUTO POSITION. ACFT GROUNDED. NR 1 CABIN PRESSURE CONTROLLER HAD LRU FAULT, RAN NR 1 CABIN PRESSURE SYS GROUND TEST IAW AMM 21-31-00-700-802, NO FAULTS AND INITIAL FAULT DID NOT RETURN. SUSPECT INTERMITTENT SOFTWARE FAULT. RESET SYS AND REPEATED TEST AND ONCE AGAIN, NO FAULTS. COMPUTER HAD NO RECORDED FAULTS AND THERE WERE NO FAULTS LAST 30 DAYS IN TRAX HISTORY. GROUND FUNCTIONAL TEST GOOD IAW AMM 21-31-00-700-802, ACFT READY FOR CONTINUED SERVICE.