As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING ENGINE START LEFT ENGINE GOT CAUTION: L ENG PRV WITH LEFT BLEED LIGHT. AFTER EXTENSIVE TROUBLE SHOOTING OF LT PNEUMATIC SYSTEM. FOUND WATER INSIDE OF SENSE LINE PORT OF OVER PRESSURE SWITCH. REPLACED OVER PRESSURE SWITCH PER MM 36-21-03. ALSO COMPLETED OPS CHECK OF SWITCH NO DEFECTS NOTED. RAN ENGINE FOR 5 MINUTES NO FAULTS. AC OK FOR SERVICE