What exactly is this? I've never heard of this before owning my Disco, just curious as to nature of it's function. I've heard it recirculates the air to burn off more fumes to reduce emissions, which makes sense based on what I can see. True?

 

Hi there,

The secondary air injection pump simply injects air into the exhaust ahead of the catalytic converter to aid in the breakdown of emissions gasses. Basically it improves catalyst efficiency. Hope this helps!

DiscoPhil

 

Real common on many cars and trucks over the last 15 plus years, I was just lucky not to get one on my 99 D2.
Mike