Just Replaced Exhaust System Now Oxygen Sensor Code

[bear15]

We have a 2004 Toyota Sequoia with 86,000 miles and just had the entire exhaust system replaced from the manifolds all the way back to the tailpipe (including catalytic converters) at a muffler shop. After driving it for 200 miles or so the check engine light came on and the code indicates a problem with both Oxygen Sensors.

Any ideas on what might be causing this and possible solutions?

Thanks, Ed

 

[kennythewelder]

Is this an OE replacement system, or a performance up grade, or something else ? The ECMs in Toyota's are sensitive to this. As far a fix, well you can always have the rear 02 sensors tuned out of the ECM, if you can find a place that will do this, but this isn't cheap, and there is the issue of passing emissions testing. The exhaust shop should make this good. Also the rear 02 sensors just tell the ECM that the cats are working. It won't heart any thing to run the truck like this, but as you know the VSS and TRAC is off.

 

[bear15]

Thank you very much for the information. It is an after market system, but not a performance upgrade. Do you think it could it be as simple as an air leak and something just did not get tightened properly?

Is this an OE replacement system, or a performance up grade, or something else ? The ECMs in Toyota's are sensitive to this. As far a fix, well you can always have the rear 02 sensors tuned out of the ECM, if you can find a place that will do this, but this isn't cheap, and there is the issue of passing emissions testing. The exhaust shop should make this good. Also the rear 02 sensors just tell the ECM that the cats are working. It won't heart any thing to run the truck like this, but as you know the VSS and TRAC is off.

 

[tibadoe]

Seems to be somewhat of a common problem for this year range of Sequoias. Were the O2 sensors replaced when they installed the new exhaust system? If not, have the codes cleared and see if they immediately come back. If they do you may be looking at replacing both O2 sensors. Let us know what happens next.

 

[bear15]

No, the sensors were not replaced. We cleared the codes and the check engine light did not come back on immediately. Do you think it could it be as simple as an air leak and something just did not get tightened properly?

Seems to be somewhat of a common problem for this year range of Sequoias. Were the O2 sensors replaced when they installed the new exhaust system? If not, have the codes cleared and see if they immediately come back. If they do you may be looking at replacing both O2 sensors. Let us know what happens next.

 

[bear15]

It sounds like we may need to replace both sensors. If so, any suggestions on a place we can purchase them for a good price? Also, is this a fairly easy installation knowing we are working with new parts?

No, the sensors were not replaced. We cleared the codes and the check engine light did not come back on immediately. Do you think it could it be as simple as an air leak and something just did not get tightened properly?

 

[kennythewelder]

Yes, it could be a leak in the system, but you should be able to hear that. As for replacing the sensors, most auto part stores carry them, or can get them, Denso brand is what you want. These are OE. You need to have the codes read to see if the sensors are reading to rich to lean, or if it is a heater failure. Keep in mind, that all 4 sensors work together. The front sensors adjust fuel trim, and the ECM compares the readings of the back sensors to what the front sensors are reading to see that the cats are still there and working, by looking at the difference between how much oxygen is in the exhaust.

 

[tibadoe]

No, the sensors were not replaced. We cleared the codes and the check engine light did not come back on immediately. Do you think it could it be as simple as an air leak and something just did not get tightened properly?

I don't think it's just a simple air leak at the sensors. Usually when they are reinserted it's a pretty snug fit. To check the rest of the exhaust, put your hand over the end of the exhaust while idling and listen for any leaks/whistling.

 

[tibadoe]

It sounds like we may need to replace both sensors. If so, any suggestions on a place we can purchase them for a good price? Also, is this a fairly easy installation knowing we are working with new parts?

I would call a dealer, or check out some parts houses and get the part #'s and their prices. Then a search online of the part #'s should lead you to the best cost.

 

[1 bad tacoma]

If it was me I would find a o2 delete kit for it I did it to my Tacoma plus I got rid of 2 cats with long tube headers

 

[bear15]

Well I purchased 2 DENSO 234-4162 Oxgen Sensors and plan to install them next week. Although I had no engine lights on before they worked on it, the shop said they should have been replaced during the job and would not take any blame-- oh well.

Any tips/tricks I should be aware of before I do the installation?

Thanks, ed

If it was me I would find a o2 delete kit for it I did it to my Tacoma plus I got rid of 2 cats with long tube headers

 

[tibadoe]

Well I purchased 2 DENSO 234-4162 Oxgen Sensors and plan to install them next week..............Any tips/tricks I should be aware of before I do the installation?

Thanks, ed

The install should be pretty straight forward. Unplug and remove old sensors. Make sure you do not touch the part of the new sensors that go inside the pipe/converter with bare fingers. Oils from your fingers can cause problems down the road. Wouldn't hurt to use a anti-seize on threads. Snug them good to prevent leaks. Here is a quick How - to article:

How to Change an Oxygen Sensor

 

[bear15]

Many thanks!

The install should be pretty straight forward. Unplug and remove old sensors. Make sure you do not touch the part of the new sensors that go inside the pipe/converter with bare fingers. Oils from your fingers can cause problems down the road. Wouldn't hurt to use a anti-seize on threads. Snug them good to prevent leaks. Here is a quick How - to article:

How to Change an Oxygen Sensor

 

[bear15]

If changing the sensors does not fix it, which I am told it is not likely, we may need to go this route. Can you help us with how to find an 02 delete kit and what is involved in completing the job? Thanks for any help, Ed

If it was me I would find a o2 delete kit for it I did it to my Tacoma plus I got rid of 2 cats with long tube headers

 

[kennythewelder]

Here is a set I made for my 4 runner. I have a set on my 97 Chevy Silverado, and they work grate, but when I made these, they didn't work on my 4 runner. You need to do a live time code read on your truck and find out why the code is happening. Here is a few pics of what I made. I have had these on my chevy for about a year and a half. The little honeycomb looking parts are out of my cats from my chevy. I gutted these cats and this is what was inside. I ground it down to fit inside of the spark plug spacers.

 

[kennythewelder]

Here is a video on how to make them yourself

 

[bear15]

Thank you very much for the awesome information! The sensors, however, on the 2004 Sequoia are non-threaded and they are bolted in place with 2 separate bolts. The spark plug non-foulers/spacers will not work with this type.

Is there another way to do this with the type we have in the 04 Sequoia that you know of?

Also, do you know how this would effect emission testing?

Thanks, Ed

Here is a set I made for my 4 runner. I have a set on my 97 Chevy Silverado, and they work grate, but when I made these, they didn't work on my 4 runner. You need to do a live time code read on your truck and find out why the code is happening. Here is a few pics of what I made. I have had these on my chevy for about a year and a half. The little honeycomb looking parts are out of my cats from my chevy. I gutted these cats and this is what was inside. I ground it down to fit inside of the spark plug spacers.View attachment 5791 View attachment 5792 View attachment 5793 View attachment 5794 View attachment 5795 View attachment 5796

 

[kennythewelder]

You will need to do some research, but I think this what you are looking for. As for emission testing, well if they put a probe in the tail pipe, then no. Each state is different. Where I live, as long as there is no CEL, then you are good most of the time.

 

[bear15]

I am sorry. I am not sure what u-tube clip I should be viewing.

You will need to do some research, but I think this what you are looking for. As for emission testing, well if they put a probe in the tail pipe, then no. Each state is different. Where I live, as long as there is no CEL, then you are good most of the time.

 

[kennythewelder]

OK let me try again