While doing some maintenance on my sons 2006 TL with auto trans, I noticed a hose missing from both ends of the smaller metal tube shown in the picture. The larger tube connects to the intake tube, but could not find anything missing a hose. I spent quite a while searching the internet for vacuum diagrams that would show it, but have yet to find one so posting here as I’m sure this will be a lay-up for many on this forum. Thanks in advance.

 

Your missing hose seems to connect the coolant passage to the throttle body. I don't know why they would need connecting.

 

I found better diagram. It seems you are missing hoses 5 and 6.

 

Thanks for the response and pictures, this is helpful. Not sure why this would have been disconnected, but will look into it and add the hoses.

 

Someone did a coolant bypass for the throttle body.

 

^yes, exactly. Not horrible from what I’ve read. And could have a purpose. 😉🤓

 

Thanks for the input. Engine runs great so will probably just leave it alone.

 

I've heard it's there to prevent the throttle body valve from sticking in really cold climates.

 

Note to self: Don't forget to clean the TB before winter.

 

Good call on the throttle body cleaning, did mine while I was in there!