P0141 indicate bad cat coverter?

[1985taylor1925]

The check engine light came on today, so I took it autozone to see what code it was throwing. It read p0141. Is this the o2 sensor downstream of the cat converter? And does it possibly indicate that my cat converter is bad?

Throughout the past several summer when the temps are warmer, when I get the truck going above 50 and then slow down while the windows are rolled down, there is a terribly strong rotten eggs type smell that permeates the cabin. My research has told me the smell is caused by a bad cat converter. So Im thinking it would make sense that the 02 sensor has gone bad.

So that in mind, should I be concerned about getting it replaced quickly? From what I read on a few other threads, the sensor downstream of the cat doesn't play any part in helping the ecu tune air/fuel ratio. Is that correct? And then lastly, for those of you who have replaced them, should I go oem or will aftermarket suffice? Never replaced an o2 sensor, so this is new territory for me.

Thanks in advance guys

 

[TheDurk]

The check engine light came on today, so I took it autozone to see what code it was throwing. It read p0141. Is this the o2 sensor downstream of the cat converter? And does it possibly indicate that my cat converter is bad?

Throughout the past several summer when the temps are warmer, when I get the truck going above 50 and then slow down while the windows are rolled down, there is a terribly strong rotten eggs type smell that permeates the cabin. My research has told me the smell is caused by a bad cat converter. So Im thinking it would make sense that the 02 sensor has gone bad.

So that in mind, should I be concerned about getting it replaced quickly? From what I read on a few other threads, the sensor downstream of the cat doesn't play any part in helping the ecu tune air/fuel ratio. Is that correct? And then lastly, for those of you who have replaced them, should I go oem or will aftermarket suffice? Never replaced an o2 sensor, so this is new territory for me.

Thanks in advance guys

Yes, that is the downstream sensor. By itself, it is strictly a heater failure code (the resistance that warms up the sensor) and says nothing about the state of the cat. So no, other than the light, there is no performance reason to change a downstream sensor. And yes, get an OEM Denso sensor. The prices on Amazon are low enough that the cheapies are just not worth saving a mere $5 or so on. Get a Denso.

The egg smell is a different story. Your cat is dying and may be plugged or will be soon and this CAN have serious performance issues. Swap your sensor and you will probably get a P0420. The dead heater is why you haven't got it yet.

 

[1985taylor1925]

Yes, that is the downstream sensor. By itself, it is strictly a heater failure code (the resistance that warms up the sensor) and says nothing about the state of the cat. So no, other than the light, there is no performance reason to change a downstream sensor. And yes, get an OEM Denso sensor. The prices on Amazon are low enough that the cheapies are just not worth saving a mere $5 or so on. Get a Denso.

The egg smell is a different story. Your cat is dying and may be plugged or will be soon and this CAN have serious performance issues. Swap your sensor and you will probably get a P0420. The dead heater is why you haven't got it yet.

TheDurk, what do you think of this article?


Understanding and diagnosing Toyota P0420 DTC - Automotive Service Professional

 

[gamefreakgc]

Yeah rotten eggs is definitely a bad catalytic converter. It's not converting the exhaust gases into the tame carbon dioxide, water, nitrogen and oxygen anymore.

There's a big difference between getting an error code and smelling potentially polluting and toxic gases coming from your exhaust. Unless you have an exhaust leak?

 

[jeremyc74]

Is your truck a CA Emissions version?

If so, I'm not entirely sure that the rear sensor has no effect on long term ECU trims. I had a P0420 on mine and ran it like that for a while. It first started throwing the code when I went up north for Thanksgiving and hit cold weather, and then it went away. Then when I went up for Christmas it came back. I was in OH working for the whole month of January and it was on the whole time, and my mileage was just horrible. I'm talking about 14MPG on the highway for several tanks.

When I got back to FL I reset it, and it came back, and I was noticing a strong smell as the truck was warming up. I assumed it was the converter, but decided to spend $50 and change the sensor. It's been several weeks now, and the code hasn't returned, and it seems to me that the smell isn't as bad either. Obviously I don't have a calibrated nose, but I don't have a stored code anymore either, so I have to assume the cat is operating within spec.

My experience aligns pretty well with what the guy in the article is saying. I've owned almost 40 vehicles (most of them with a lot of miles on them) and I've only ever had one converter actually go bad. That was on a BMW 318ti that I drove for a week in the winter time with the thermostat stuck open. The car wouldn't come up to temp without putting cardboard over the radiator, and about two weeks after I got back to FL it needed a new converter (clogged to the point it wouldn't run). Other than that I've never had to change one.

Short of it....I'd change the rear O2 sensor and see what happens. It's a lot cheaper and easier than changing the cats. :heh:

 

[MONTYMTB]

[MENTION=56756]1985taylor1925[/MENTION] Have you read this?
If the sensors on your truck have never been replaced, it's probably a good idea to do it. Recommend going with the Denso (assuming non-Cali).

 

[jeremyc74]

[MENTION=56756]1985taylor1925[/MENTION] Have you read this?
If the sensors on your truck have never been replaced, it's probably a good idea to do it. Recommend going with the Denso (assuming non-Cali).

Rock Auto has the Denso Cali sensors for about $50 too. Dealer wants like $200 for them! :suspicious:

 

[1985taylor1925]

Yeah rotten eggs is definitely a bad catalytic converter. It's not converting the exhaust gases into the tame carbon dioxide, water, nitrogen and oxygen anymore.

There's a big difference between getting an error code and smelling potentially polluting and toxic gases coming from your exhaust. Unless you have an exhaust leak?

I don't suspect that I have any exhaust leaks, but if I did would it be the rotten eggs smell?

 

[gamefreakgc]

It could if the leak is before the cat. If it's after the rear O2 it doesn't really matter much (other than being loud).

The easiest ways to check for exhaust leaks is one of two methods:

1. Seafoam your rig and look for smoke coming out anywhere except for the tailpipe
2. Take a 3 foot length of hose and place one end to your ear and the other to "scan" the exhaust pipes (don't burn yourself!). You'll be listening for a puffing or hissing noise. Focus on weld points and any areas with rust.

I'm not guaranteeing it's an exhaust leak, but it's easy enough to check and rule it out.

 

[73Duster440]

I have same rotten egg smell and was contemplating just replacing the cat when I toss a new borla on along with O2s and some other goodies

 

[1985taylor1925]

Still haven't gotten around to changing the o2 sensor as Ive been really sick with an illness the dr cant figure out at this point.

So there are four different denso 02 sensors listed at the top of this page on amazon, all of which say they are for reading exhaust gases, all are compatible with our 3rd gens, and all with different part numbers. Anyone know which one of these four I would need for my p0141 code?


Amazon.com: Oxygen - Sensors: Automotive

 

[kball]

Here's your sensors.

1996-1998 Auto 4WD V6 3.4; Front = 234-4162
1996-1998 Auto 4WD V6 3.4; Rear = 234-4154

Has your doctor checked for West Nile Virus? I've heard it's making it's way to areas it hasn't been before.

 

[1985taylor1925]

Here's your sensors.

1996-1998 Auto 4WD V6 3.4; Front = 234-4162
1996-1998 Auto 4WD V6 3.4; Rear = 234-4154

Has your doctor checked for West Nile Virus? I've heard it's making it's way to areas it hasn't been before.

Thank you sir.

I was tested for influenza and mono, along with a bunch of other things in my blood work. Unfortunately its looking like something a little more long term. Some sort of autoimmune disorder. Im praying its nothing too serious.