What was found
ON INITIAL CLIMB OUT, OIL PRESS LOW L MASTER CAUTION OBSERVED. PRESSURE WENT DOWN TO 22-25 PSI. TEMP ROSE BUT NOT TO POINT OF YELLOW OR RED. RETURNED TO AIRPORT. PERFORMED #1 ENG LOW OIL PRESSURE TROUBLESHOOTING IAW LMM: 72-00-00, PERFORMED #1 & #2 ENG DOWNLOADS, FILE UPLOADED TO HONEYWELL. RAN #1 ENG ON IDLE, NO DROP IN OIL PRESSURE, MOVED POWER LEVEL TO 85% N2 FOR 3 MINS, NO DROP IN OIL PRESSURE. NO OIL PRESS LOW L CAS MESSAGES NOTED, OIL PRESSURE & TEMPS WERE WITHIN LIMITS DURING RUNS. REPLACED #1 ENG OIL PRESSURE TRANSMITTER IAW LMM: 79-30-03 & SWAPPED #1 & #2 ENG W4 HARNESS IAW LMM: 76-10-01, RAN BOTH ENGINE TO 85% N1 FOR 5 MINS EACH, OIL PRESSURE & OIL TEMP REMAINED NORMAL RANGE.