What was found
ON DEPARTURE AIR SYS, MANIFOLD ILLUMINATED RED MOMENTARILY. LEVEL 2 ALERT WING ANTI ICE LIGHT. DIVERTED. LANDED UNEVENTFULLY. MANIFOLD FAIL ALERT CAME ON BEFORE WING ANTI ICE ALERT RECEIVED. ESC FAULT REVIEW SHOWS LT WING ANTI-ICE MANIFOLD & PSC-2 STORED LT WING ANTI ICE MANIFOLD FAIL. NO FAULT ON PSC-1 AND MFD. PERFORMED ANTI-ICE VALVE AND DUCT AIR LEAK CHECKED AND FOUND ALL TEST PASSED. CHECKED WIRES BTW DIP SENSOR AND SPEC, FOUND NO DEFECTS. CHECKED MFD LOOP SEL 1 AND SEL 4, FOUND NO SHORT TO GROUND. SUSPECT TIME DELAY FOR LT ANTI ICE MANIFOLD FAIL IN PSC-2 DID NOT WORK. R & R PSC-2, P SENSOR IAW MM. OPS CHECKED VALVE & SENSOR & ALL OPS NORMAL PSC-2 RTS TESTED & ALL TEST PASSED. ACFT RETURNED TO SERVICE.