As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WING ANTI-ICE VALVE INOP, FLIGHT DIVERTED. CREW REPORTS WHEN WING ANTI-ICE TURNED ON, THE RT WING VALVE LIGHT DOES NOT COME ON. THERE IS A DUCT PRESSURE DROP RT SIDE AND LT SIDE WITH ISO VLV CLOSED. CONFIRMED VALVE OPS BY PNEU PRESS DROP & EGT RISE DURING ENG RUN WITH CREW. INOP IAW MEL. SYS DEFERRED. LATER, CLEANED THE CONNECTOR AND OPS CHECKED THE SYS OK. REF SVC TIP AND OP CHKS IAW AMM. NO PROBLEMS SINCE.