At what XM level does your scanner get disabled?
Solution 1:
Some observations:
Scanner Disabled seems to be an actual number threshold. I have got to around 2% XM (as an L6) and been allowed to hack one last portal before it was disabled. This suggests to me that the limit could be 150 XM (2% of 6k = 160 XM, so 150 is a reasonable 'rounded' value that may apply)
Scanner Re-enabling is a different threshold, and could be on percentage basis. From L1-L6, it recovers slightly before 10% is filled up ... maybe 9% of total XM?