Inconsistent IF Results

CELL A1 CONTAINS "4.030"
CELL B1 CONTAINS "4.015"
CELL C1 HAS THIS FORMULA =SUM(A1-B1).....IN THIS CASE THE SUM IS ".015"
CELL D1 HAS THIS FORMULA =IF(C1>0.015,"FAIL","PASS"), BUT......
IT RETURNS "FAIL", ANYTHING OVER OR UNDER THE EXACT NUMBER WORKS FINE, BUT THE EXACT NUMBER ISN'T ACTING RIGHT!
ALSO, IF I REMOVE THE FORMULA FROM C1 & MANUALLY TYPE ".015" INTO THE CELL IT WORKS GREAT AS WELL.
HELP ME!!!!!!
please

@BW29, please note that your thread title falls foul of Forum Rules.

Your post title should accurately and concisely describe your problem - in this case perhaps something along the lines of: "Inconsistent IF Results"
(I appreciate in this instance it probably isn't obvious how to best describe given the Rounding issue is not obvious - on that basis I have on this occasion modified for you).

Please also avoid posting in CAPS - this is in forum-geek terms interpreted as shouting.

Regards solution - you can just round the result:

D1: 
=IF(ROUND(C1,3)>0.015,"FAIL","PASS")

or, if you prefer to dispense with C1 altogether:

D1:
=IF(ROUND(A1-B1,3)>0.015,"FAIL","PASS")

Note the use of SUM in SUM(A1-B1) is superfluous.

Thanks