Diagnostic Code 72

[indiemo]

Hey all. Driving home from a roadtrip to North Carolina this weekend, the check engine light on my TJ popped on. Ran the diagnostic and got code 72, which when translated says, "Catalyst efficiency below required level". Is this an O2 sensor problem or something else?

From the amount of rattling underneath, I'm pretty sure the cat is shot and was planning on replacing it anyway, but it's still a little cold to be laying out in the driveway. Anyone got any tips for replacing the cat? Will I have to remove that skid plate that covers the transfer case and everything or can I get away with working around it? I can probably figure it out if I get a chance to look at it, but thought I'd see what y'all had to say first.[addsig]

	Transfer Case Mounted behind and driven by the vehicle transmission, the transfer case transmits power to the front and rear driveshafts in 4WD Jeep vehicles and offers high and low range.

[Jeepin91]

I have a YJ myself but things are pretty much all the same here. My cat went bad on my rid a month or two ago. I think it mostly went out with age and the fact that I put it underwater a lot. Even if you have not wheeled it so hard that you have submerged the cat it can still go bad. When I took mine out I did have to drop my skid. I didnt completely take it off I just dropped it a few inches and supported it with two jackstads. That gave me enough room to get in there and work.

My advice is when you change it go to a HIGH FLOW cat. It makes a huge difference. You will not be sorry. And make sure that you get your muffler checked also. When mine went bad it blew chuncks of my Cat into my muffler and I ended up having to replace it also. Good luck :-P [addsig]

[indiemo]

Thanks for the tips Jeepin. Guess I'll have to go steal my jackstands back off my dad.

I was planning on getting a high flow cat. The only one I've found is that Random Technologies unit that Quadratec sells. Anyone have any experience with this one or know a better (or cheaper) one out there. I've also been looking at new cat-back systems. I figure I might as well put one on while I'm underneath there. It'll depend on how much I mess up the current exhaust trying to get the cat off. I have a Pacesetter on it now, which I like. It's got a really good note but not obnoxiously loud. So I'm trying to decide which one of those I want too. [addsig]

[Bounty__Hunter]

DC should replace the converter for free if, IF, you're within the Federal Emissions Warranty of 8yr/80,000 mi.

For a hi-flow, Rusty's Offroad has one for under $100, it's what I run. JC Whitney has a Catco (same brand as what Rusty's sells) for about $60 :-D [addsig]

[JeepGuyNY]

Indiemo,
First do you have more than 80,000 miles on it. Reason I ask this is cat converters are covered by Jeep up until 80,000 miles. At least it is that way in New York state, I found out the hard way I had 80,100 miles when mine went. Also if you never want to replace it again get the random technologies cat converter, it is stainless and allows better air flow. If you plan on keeping your jeep a while that is the way to go . You never have to replace it again. They guarantee it is legal in all 50 states. Go to www.quadratec.com .. [addsig]

[indiemo]

Thanks for the heads up JeepGuy. I only have 72K on my Jeep, but I'm not looking to replace the cat with and OEM one, so I don't think this will apply to me. I'd rather put on a high flow piece. It looks like I'll probably end up going with the random technologies cat. thanks for the advice![addsig]

[dingus]

go get the dealer to slap one on there (stock replacement) and then buy a hi-flow cat... when you go to put the high-flow one on there the bolts'll won't all be seized! then you can sell the stock one (or give it to me!)

-nate[addsig]

[indiemo]

dingus, that is perhaps the single greatest idea I've ever heard. I'm calling the dealership this afternoon.

edited by: indiemo, Mar 11, 2003 - 10:37 AM[addsig]

[Bounty__Hunter]

New catalytic converters are not as restrictive as you may think, the dealer one should flow just fine, doubt you'd notice the difference.[addsig]