I need to pass the smog test in a couple of months. Does anyone have experience with the first code, PO411 exhaust air system or the other two which are catalyst codes? My car is a '97 XJ6 with the 4.0 six. Any help will be appreciated. Thanks.

 

0411 is most commonly failure of the meddlesome air pump - way up front next to your air inlet box. It has a plastic housing, two hoses and a wiring loom attached to it Could be the wiring, though, as I have a 95 that has always sported the P0411 and one day I pulled the pump off, shook it, dug at it, tried to open it...and got lots and lots of rust bits out of it, but the mechanism was clearly frozen, so I fit a known good pump (you can hear them quite clearly when they run) from another car, and no joy. Noticed a blown fuse (forget where it is, though) and replaced it. Blown again. Read the TSB's and found there was one saying to inc the amperage of the air pump fuse. Sorry, also forget from what to what...but did that...still blew. FWIW, it sucks air out of the air filter box and blows it into the exhaust. This is supposed to make the greenies happy. Here in rural Texas we don't truck with that emissions crap so much...so no harm no foul on the 95, Although it is supposed to help with the catalyzing of the exhaust somehow or another, Mine never caused the 420 nor 430 catalyst codes.

The pump is alleged to be identical to one used on a certain model Corvette, late 80's or early 90's I think, but can't recall for sure. Anyway, reports are that replacements are a bit cheaper if the seller thinks you will be fitting it to a 'Vette vice a Jag.

 

Pumps are identical to a 95 Buick Roadmaster with a 350. Change the check valve and the P0411 should go away