Capped Wire In Engine Bay

[EastEndAngler]

Was poking around my engine bay today and found this wire taped back by the IWE check valve. It's a purple wire, perhaps 16 awg, capped/dipped just like the aux switch wires. Anyone know what this is for?

 

[Antho]

Some models have a (MAF/IAT) sensor at connector 129. Ours only has IAT. Looks like that wire just comes pre wired in that harness.