Good morning 

Not a lot of time for the Subaru this last 18 month or so😪, but was poking about the other day and found this and was wondering if anyone could shed light on why its disconnected. 

Thanks Neil 

Anyone?

I'm guessing it was done when new ECU was fitted 

Sorry bud , didn't spot this post 1st time.

That's a barometric sensor , used to measure atmospheric air pressure,  so the ECU knows the density of the air coming into the engine to adjust fuelling. 

What type is the "new ecu" ?

As most mappers tend to still leave that sensor connected to help with fuel trims 

Thanks savage 

I've got alkatec running mafless with added air temp sensor in the inlet 

Having a aftermarket ait is probably why it's unplugged , as the ECU is able to read the air temperature . Not quite as good as having the atmospheric pressure as well but a ait does help with maf less fuel trims 

Thanks I feel a bit better about it now