I had my car (1996 Volvo 850 2.4L N/a 5-Speed) OBD II tested and got the error code P0455 - EVAP System Large Leak. Is there anywhere I should look first or any means of tracking down the source of the leak? Are there any side affects I should be on the look out for to narrow the diagnoses or anything in general I should be aware of?
Thanks for any input!
-Luke

 

Gas cap... is it on, is it tight (use the 3 click rule on a fill-up) and is the o-ring there without any cracks or missing chunks.

As far as side affects you shouldn't notice anything. You are potentially leaking unfiltered gas vapor into the atmosphere.

 

check the hoses back by the tank - not sure if the 96/97s 850s share the same J-hose design as the 98+ V70s but that's a common cause in those models... search Youtube for "volvo j hose" for ideas.

 

Gas cap
Hole in the charcoal canister
Deteriorated rubber hose connection
Cracked plastic hose
J hose on top of tank
Small hoses on each side of the purge valve by the fuel pump
Small hose connection between the subframe and the body

All places to look but aside from the fuel cap the J hose is the most common and you can pretty much pin point that one by filling your fuel tank full and see if you leak fuel on the ground.

 

I am not a professional mechanic, but I gathered the modern way to hunt these evap leaks is with a smoke machine which is fairly expensive, but I guess that makes it easy. Some of my vehicles have a dedicated smoke machine hookup point.

 

All of them should, and easily found by the green cap covering a schrader valve. I'm just a bigger fan of checking the usual suspects and free things first.