Will bad downstream O2 sensors cause the upstream O2 sensors to go bad?

Leahatrill

Leahatrill

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Does anyone know if having 2 bad downstream 02 sensors will cause the upstream to go bad?

Last week after over an hour in traffic I noticed my Jeep jerking hitting 2200rpm. Pulled over and checked for a code and got 0344 which is the camshaft sensor. Replaced. Accompanied with it though was a 0038 code which is b1s2 02 code. As I drove longer etc p0132, p0152, p0058, p0038 all turned on which is all my 02 sensors....even b1s1 is showing and I just replaced it the day prior. What’s causing this to happen? My cat doesn’t seem to be bad. New camshaft sensor. I don’t think there’s any vacuum leaks. Nothing indicating my pcm is bad because my Jeep fires up immediately etc. Soaked 02sensors in gas for 10 hours yesterday and reinstalled and it made my engine misfire like crazy initially and idle so poorly almost to the point of stalling. Bought 3 new sensors today and replacing tomorrow.

Could it just be my sensors are done and it’s time to change them ? What I don’t understand is why 0132 is showing when I just replaced that sensor yesterday — is it because all of them are shot so it’s throwing that one off too or? Both downstream were replaced 1 year ago. Upstream bank 2 I have never replaced since I bought my Jeep like 8 years ago.
 
Always ngk sensors yes. Just really weird timing is all.
B1s1 do you think this one will need replacing again even though it’s brand new? 0132 is coming up. Is it coming up because the downstream is bad etc ? I’m replacing all 3 tomorrow morning except for b1s1 because it’s new — I’m paranoid in not replacing it again tho for it maybe damaging the others or smething ?
 
Leahatrill said:
Could it just be my sensors are done and it’s time to change them ?
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Absolutely! O2 sensors are general wear and tear maintenance items and should be replaced around every 80k miles regardless of whether there is a check engine light. You need to change them just like any other scheduled maintenance.

In addition, how do you know your pre-cats aren't bad? The symptoms you describe sound exactly like those of a bad cat.
 
Chris said:
Absolutely! O2 sensors are general wear and tear maintenance items and should be replaced around every 80k miles regardless of whether there is a check engine light. You need to change them just like any other scheduled maintenance.

In addition, how do you know your pre-cats aren't bad? The symptoms you describe sound exactly like those of a bad cat.
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This just happened to me. Intermittent check engine light for downstream O2 sensor. Shop did a smoke test on it and one of the pre-cats was cracked. Wound up replacing the entire exhaust system along with the O2 sensors. All good now.
 
Bud125 said:
This just happened to me. Intermittent check engine light for downstream O2 sensor. Shop did a smoke test on it and one of the pre-cats was cracked. Wound up replacing the entire exhaust system along with the O2 sensors. All good now.
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Yep, when my pre-cats failed my symptoms were exactly like the OP is describing. O2 sensors rarely all go bad at once, so I suspect that is his issue, the pre-cats.
 
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My precats...Urgh....I had the entire exhaust replaced 2 years ago ....maybe it is the cats .....how do I know for sure it’s them before taking that stupid thing out?
 
If I were to remove all my 02 sensors and take a drive and my performance has improved etc im assuming this would be a good indication it’s my cats right?

I bought the whole exhaust feb 28 2018 it’s still under warranty so I’m pretty sure I’ll be getting it’s for free tbh if it already is bad.
 
This almost sounds like the computer going bad which an issue with the 05-06 models. The two most common symptoms I’ve seen regarding that issue is hard shifts with the auto transmission, or the entire o2 circuit going dead and throwing codes like you described.

O2 sensors need to be periodically changed like mentioned above, but they rarely all go bad at once like you’re describing. I suspect a faulty PCM, but change the other three sensors with the NTK ones first just to rule bad sensors out.

Bad or clogged cats usually cause a “stumbling” feeling from the engine or power loss.
 
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I doubt it’s a bad computer. Thought about that already though. The symptoms I described can be caused by a lot of other things then the brain to my engine. My engine fires up immediately and hasn’t shown any other symptoms other then 02 sensor codes and bad gas mileage. The fuel/air ratio is way off.

..wont be replacing the brand new sensors until I figure out if my pre-cats are bad. thanks
 
If you had the entire exhaust system (including both pre-cats) replaced 2 years ago, then it is unlikely that the cats are the issue. I only bring them up because when mine failed, my symptoms were nearly identical to yours.

I didn't smell rotten eggs either, but when I took them apart there was stuff rattling around inside there. In addition, often times when they are bad they will get to the point where when you are driving, they will start to glow red due to the heat.
 
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Chris said:
If you had the entire exhaust system (including both pre-cats) replaced 2 years ago, then it is unlikely that the cats are the issue. I only bring them up because when mine failed, my symptoms were nearly identical to yours.

I didn't smell rotten eggs either, but when I took them apart there was stuff rattling around inside there. In addition, often times when they are bad they will get to the point where when you are driving, they will start to glow red due to the heat.
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Yup! Agree with this all. Tomorrow I’m going to try tapping on them both to see if I can hear anything rattling. I heard smething this morning when I first started my Jeep but I couldn’t pinpoint where it was coming from ....
 
You're certain when you had the exhaust replaced that they replaced all three catalytic converters as well?
 
Chris said:
You're certain when you had the exhaust replaced that they replaced all three catalytic converters as well?
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I did it myself. Yes. Feb 28/2018.

I might add this. 2 days before 0344 popped up along with 0038 and I replaced the camshaft position sensor etc. I took the skid plate off and cut the rear cat off and replaced with a straight pipe to see if I could increase my horsepower and overal performance etc ... after replacing the CPS I decided to reinstall the rear cat again. I then replaced the b1s1 sensor. The following day along with 0038 I got 0058, 0152 and then later on got 0132 Even though just replaced it. The week before that was my power steering pump. It blew and got fluid all over my engine. Could this have maybe caused all this trouble? This Jeep lately ....holy hell

3DD9FB45-5982-4A33-9AE8-218CC2530792.jpeg
 
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Never rule out loose pre cats ...that totally confuses the O2 sensors...because it admits cold air.

Also , I don't know what's on that door panel , but I bet it matches some paint in your house ..soak it in Go Jo hand cleaner .

Remember the 4 pre cat bolts can seem tight but be corroded , pre spray in penetrant, expect a smell as it burns off.
 
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AndyG said:
Never rule out loose pre cats ...that totally confuses the O2 sensors...because it admits cold air.

Also , I don't know what's on that door panel , but I bet it matches some paint in your house ..soak it in Go Jo hand cleaner .

Remember the 4 pre cat bolts can seem tight but be corroded , pre spray in penetrant, expect a smell as it burns off.
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Hahahah I’m a paint contractor.
 
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Leahatrill said:
Hahahah I’m a paint contractor.
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Awesome.

I was a tile setter and finish carpenter before I became a remodeling contractor in Huntsville , and my #1 painter is a woman , she is excellent , pays attention to detail, and watches out for the company and clients.

My dad was a painter as well , and my uncle was a huge paint and drywall contractor years ago ..so I have a great respect for it .

Keep your chin up every day, it is just as respectable to be a good trades person as it is a surgeon or anything . The world often needs to be made more beautiful. What you do makes a difference ..a good paint job makes a home.
 
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AndyG said:
Awesome.

I was a tile setter and finish carpenter before I became a remodeling contractor in Huntsville , and my #1 painter is a woman , she is excellent , pays attention to detail, and watches out for the company and clients.

My dad was a painter as well , and my uncle was a huge paint and drywall contractor years ago ..so I have a great respect for it .

Keep your chin up every day, it is just as respectable to be a good trades person as it is a surgeon or anything . The world often needs to be made more beautiful. What you do makes a difference ..a good paint job makes a home.
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Awww! Thanks! :)
 
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