What was found
ON DECK AT IDLE, NR 1 FILTER BYPASS ILLUMINATED FOR APPROXIMATELY 2 MINUTES, THEN WENT OUT ON ITS OWN. NO ENGINE ABNORMALS OBSERVED. ACFT GROUNDED. FOUND FUEL FILTER DIFFERENTIAL PRESSURE SWITCH CONNECTOR PLUG LOOSE. CLEANED AND SECURED CONNECTOR PLUG ON FFDPS. REF FIM 73-05, TASK 801. IAW FIM 73-05, TASK 801, FOUND FAULT CODE 73-21071, FUEL FILTERS DISAGREE ACCOMPLISHED THE REPAIR CONFIRMATION, STEP F. IDLE POWER CHECK, TESTED GOOD.