What was found
WHILE DESCENDING THRU FL350 ENG CNTRL FAULT L EICAS ILLUM IN VMC CONDITIONS. RAN CHKLST. AFTER PUTTING ANTI-ICE ON MESSAGE WENT OUT. AFTER TURNING ANTI-ICE OFF, MESSAGE CAME BACK ON FOR A FEW MINS. MANUFACTURER RESPONDED WITH ARES SHOWING L-A FADEC HAS THROWN AN HA FAULT CODE, (ENGINE AT DISAGREES WITH ADC PT). RECOMMEND TROUBLESHOOTING PER THE P&WC EMM FOR FAULT HA. PERFORMED EMM 72-00-02, FADEC FAULT CODES H - P, FAULT ISOLATION 8 FIM TASK 101 EEC PT INPUT FAULT. PERFORMED STEP 1 OF FIM TASK DOES RESETTING EEC 28V AIRCRAFT POWER WITH THE ENGINES NOT RUNNING CLEAR FAULT. USED ONBOARD MAINT DIAGNOSTIC PAGE TO CHK IF FAULT CODE HA WAS STILL PRESENT, & FAULT CLEARED. MOVED ACFT OUTSIDE & STARTED BOTH ENGS TO TRY AND DUPLICATE FAULT. FAULT WAS NOT ABLE TO BE DUPLICATED. NO DEFECTS NOTED AT THIS TIME.