'98 Cherokee sport CHECK ENGINE LIGHT

[ASauer17]

So, as most of you know, I have a Cherokee aswell as a Wrangler.

The check engine light has come on again!

1 is a small evap leak, which I know about, and has been like that for over 2 years.. no biggie. Code P0442



NOW, the other one. Code P0420.. no idea where to begin. I really REALLY don't want to bring it to a shop just to have someone look at it then be handed an $80 bill.. any ideas?

[Kurt]

Usually the second code is due to a failing O2 sensor on the catalytic converter.

[ZAEDOCK]

I would suspect the O2 sensor as well.

[ASauer17]

I was reading on how to remove and replace the 02 sensor. Lets just hope it is as easy as it seems... I'll start there

[Kurt]

It's pretty easy. The only hard part is that they are usually rusted in place.
Generous amounts of WD-40 ahead of time helps.

They do make a special 02 sensor removal socket in case the wrench's you have on hand can't get it out.

[Carl McFly]

They do make a special 02 sensor removal socket.....

Auto Zone has free rentals on that socket

[Elwood Blues]

pb blaster the 02 sensor while the exhaust is cold, start it up until the pb smokes, shut the rig down and let the exhaust cool
do that 2 or three times and that sucker should come right out without two much trouble,
the more heat cycles the pb has to seep into the threads the better