Help with P0171 code

[DropTopDon]

If that were my jeep the first thing I would be doing is getting that upper bank 1 (front) sensor out - Even if it looks good I would replace it-



Your bank one fitment really looks better than your bank two but they’re both close enough that I would not immediately think you’re getting bad air in - unless they are loose -

What I’m thinking is you had a bad bank 1 sensor all along but you couldn’t tell it because of all your cat drama-the computer just could not isolate it til the cats were replaced -

I’m sitting in a 2006 right now- I think what you’re going through is what every owner has to do to live with the 2005/2006 models -At the first sign of failure replace the catalytic converter’s and all the sensors- it is not a defect - it is a wear item like spark plugs.

Also the rich mixture is going to make your mileage drop-

I’m not picking at you -because I’ve done the same thing- Tried to get by with not replacing more than I had to- Basically with doing only 2 oxygen sensors it’s about the equivalent of replacing three out of six spark plugs.

Keep us posted all the way- We need the information to help all of us know how these things are acting and what fixes them.

I see. My old cat was for sure shot because it would rattle like crazy and the honeycombs were no longer in tact. Maybe a bad upstream O2 sensor had something to do with my previous cat failing? Not entirely sure bc this Lj is new to me. I’ll probably fix the exhaust leak and order new NTK upstream sensors as well to see if that fixes it and if not it is still good preventative maintenance so no money wasted. Planning to go on a beach trip in 10 days so hopefully I can get the sensors and fix it asap!

 

[AndyG]

I see. My old cat was for sure shot because it would rattle like crazy and the honeycombs were no longer in tact. Maybe a bad upstream O2 sensor had something to do with my previous cat failing? Not entirely sure bc this Lj is new to me. I’ll probably fix the exhaust leak and order new NTK upstream sensors as well to see if that fixes it and if not it is still good preventative maintenance so no money wasted. Planning to go on a beach trip in 10 days so hopefully I can get the sensors and fix it asap!

It will be fine- you just have to be a little persistent-

I have been messing with these things for about five years and all three 2006 models I have had were quick to code-

It is not evil but you’re gonna have to sort some things out when you get one of these- The engine will keep running regardless and the typical owner just drive and drive these things while the emissions systems slowly fail-

I have had two of them that had catalytic converter issues - one of them just would not stop throwing codes and the media was shifted in one bank and gone in the other and the other one was like yours- it just rattled and rattled- the media was loose -

The catalytic converter’s are vulnerable just from the fact that people take these things off road and get the system real hot and it bounces around and the delicate media comes loose- The oxygen sensors lives in exhaust heat and gases and carbon and oil and sulfur and everything that’s in fuel- They are pretty amazing little devices....But they are not life time components and we’re never intended to be.

Recently there was a thread asking how bad the late model ones are- They do have some vulnerabilities but not anything that is even close to hurting their value - especially the LJ - You just have to know how to diagnose some things and be ready to freshen up the exhaust system-

I don’t know really a fraction of what many of these guys do but am learning -

The thought will enter your mind at some point that it is just one thing after another - If you will get your scanner and a few basic tools and use this forum you will learn a lot and have something that you can depend on and really enjoy.

Everyone of these needs attention that I have come across- I picked up a 2006 Rubicon and it had one check engine light and the owner was driving it every day- I have probably fixed 20 things on the vehicle- I’m not picking on him but I’m just saying that’s a typical scenario.

 

[DropTopDon]

Well. Driving to work this morning and the check engine light turned off itself. I said oh well I’ll see what happens. Then I went to an exhaust shop so they could weld my pipes together. They did that and my exhaust leak went away. Well I was there I asked them to see if there was a leak at the manifold to the cats. They listened with a scope and reported to me that there were no more leaks in the exhaust system. So driving it shut the code off itself. Not sure what caused it maybe just new cats threw something off in the system. I’m still gonna replace both upstream O2 sensors when they get here

 

[AndyG]

Dont rule out the maf sensor in the intake tube too and I’d still obd scan it
and clear it if it shows back up- let us know it stays gone.

 

[NskLJ]

Just replaced my catalytic converter on my Lj yesterday and today while driving I got a P0171 code. It means bank 1 is sensing too much oxygen. Any ideas?

P0171 is the upstream o2 sensor lean.

 

[NskLJ]

Well. Driving to work this morning and the check engine light turned off itself. I said oh well I’ll see what happens. Then I went to an exhaust shop so they could weld my pipes together. They did that and my exhaust leak went away. Well I was there I asked them to see if there was a leak at the manifold to the cats. They listened with a scope and reported to me that there were no more leaks in the exhaust system. So driving it shut the code off itself. Not sure what caused it maybe just new cats threw something off in the system. I’m still gonna replace both upstream O2 sensors when they get here

Also reset the KAM, keep alive memory dis on etc the battery when you install the o2’s then reconnect start up it will have to relearn the idle but that should put the computer back to baseline.

 

[Chiatroll]

I’m having the same issue. Replaced both o2 sensors and still have it. I have live stream data if anyone knows what to get next by looking at it. Thank you

 

[209Wrangler]

Im runing into this same issue after replacing upstream O2 with an NTK. ran fine for about 20 miles then 0171 code, and can see a considerable decrease in gas mileage, as I had to drive it about a hundred miles to work while my reg car was in the shop... Im definitely hearing the squeak from the exhaust manifold where the springs are likely worn out...is there anyway that those worn springs are causing inlet air to get into it?