P0401, P0402, and P0420 Codes All Reading

Good afternoon y'all. I've got a 2000 Tacoma with the 2.7L 3RZ-FE engine and it is 4x4. I have the codes P0401, P0402, and P0420 all reading. Since P0401 is insufficient and P0402 is excessive, I am not sure what it could be. I have already checked the EGR Valve and the EGR VSV and they are both operating correctly. I am new to the site, so if there is already a thread with similar content, please point me in the right direction! Thanks for any and all help!

 

Have you checked the EGR temperature sensor? Thats what the computer is reading to determine if things are going wrong or not. When it fails you get codes.

 

I have not checked that. To be completely honest I'm not sure where it is or how to check it. You wouldn't happen to know or be able to steer me there would you?

 

So it might be covered in this video ( I didn't have time to watch the whole thing, but he seems to go over all the components)
https://www.youtube.com/watch?v=TUX53zR0LWg

It screws into the intake manifold near the EGR. If you have a multimeter, you can check its resistance to ensure it is in range.

I attached a test procedure for it, page 3 has the bit about checking the resistance.

 

I will go through this evening and report back with what I find. Thanks for your help! I'm assuming the 2.4L will have real similar things as far as the EGR system is concerned right?

 

Yep, the 2.4 and 2.7 are almost the same engine.