As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING FLIGHT 3163 AFTER TAKEOFF ON CLIMBOUT IN ICING CONDITIONS THE RIGHT AIR VALVE LIGHT ILLUMINATED. AIR RETURN TO MSP. MAINTENANCE FOUND OIL IN CANNON PLUG 23P7, CLEANED CANNON PLUG, PERFORMED OPS CHECKS IAW GE MM APPENDEX 7. OPS CHECK GOOD.