Where does the EGR get its temperature reading from P0402 problem

Just got a P0402 code. My temp gauge started intermittently functioning about the same time. If I understand the way EGR opens and closes correctly it’s based on temperature. Does it get temp from the same place as my gauge? I don’t want to replace a bunch of parts that aren’t broke. How do I best diagnose what’s going on?

 

I had P0402 on my 2.4. Excessive gas recirculation.

There are some good trouble shooting videos on YouTube for Toyota EGR system.
This is the one I found the most useful: https://m.youtube.com/watch?v=WOSFmKY15SU

The EGR temp sensor is different than the coolant temp. I know this because I messed with the egr temp sensor and my coolant temp gauge works as it always has.

I disconnected my EGR from the vacuum line that actuates it and plugged that line. This gave me p0401, insufficient flow.

Disconnected the wiring from sensor and used a 10k resistor in place of the sensor. This lets the EGR know to stay closed.
Haynes has a chart which gives resistances that the sensor reads, with 10k being what it reads at cold. This way, with egr system inoperable, the check engine light won’t turn on claiming insufficient flow. It thinks it’s not supposed to have any flow at all.

This resistor solution has been discussed previously on other forums, search ‘egr delete check engine light’.
I was able to narrow down my problem in the EGR system to the VSV, which is located under the intake manifold, so I said fuck that, and explored simpler options.


Hope this helps.

 

That’s exactly what i

That’s what I needed. I’m a decent driveway mechanic but I don’t have very good diagnostic skills.

 

I followed that video too. Found out my valve was stuck so I replaced it and it was all good for about 500 miles. Now it’s back on and I’m sick of this EGR crap lol