Engine management light

[Drawweight]

I’ve got a 4 year old Fiesta ST Line.

Few weeks ago the light came on. I took it to my BiL’s garage who read the code. Turned out it was connected to the air conditioning. They took it off and it’s been fine since.

Today I turned the engine on and put the defrost on and left it for a few minutes. Now the light is back on.

Is there an easily replaceable sensor or something that could be causing this (big hope I know).

Anyone else had this?

[normalbloke]